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123121213 = 397310129
BaseRepresentation
bin1110101011010…
…10111000111101
322120200012112221
413111222320331
5223004334323
620114525341
73023340655
oct725527075
9276605487
10123121213
1163553876
1235296851
131c67a7b7
14124cd365
15ac2055d
hex756ae3d

123121213 has 4 divisors (see below), whose sum is σ = 123431740. Its totient is φ = 122810688.

The previous prime is 123121189. The next prime is 123121217. The reversal of 123121213 is 312121321.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 79798489 + 43322724 = 8933^2 + 6582^2 .

It is a cyclic number.

It is not a de Polignac number, because 123121213 - 213 = 123113021 is a prime.

It is a super-3 number, since 3×1231212133 (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123121217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 154668 + ... + 155461.

It is an arithmetic number, because the mean of its divisors is an integer number (30857935).

Almost surely, 2123121213 is an apocalyptic number.

It is an amenable number.

123121213 is a deficient number, since it is larger than the sum of its proper divisors (310527).

123121213 is an equidigital number, since it uses as much as digits as its factorization.

123121213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 310526.

The product of its digits is 72, while the sum is 16.

The square root of 123121213 is about 11095.9998648161. Note that the first 3 decimals coincide. The cubic root of 123121213 is about 497.4822942614.

Adding to 123121213 its reverse (312121321), we get a palindrome (435242534).

The spelling of 123121213 in words is "one hundred twenty-three million, one hundred twenty-one thousand, two hundred thirteen".

Divisors: 1 397 310129 123121213