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12121210 = 251212121
BaseRepresentation
bin101110001111…
…010001111010
3211210211011201
4232033101322
511100334320
61111444414
7205012543
oct56172172
924724151
1012121210
116929932
12408670a
13268521a
1418774ca
1510e670a
hexb8f47a

12121210 has 8 divisors (see below), whose sum is σ = 21818196. Its totient is φ = 4848480.

The previous prime is 12121157. The next prime is 12121211. The reversal of 12121210 is 1212121.

12121210 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in 2 ways, for example, as 11689561 + 431649 = 3419^2 + 657^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Harshad number since it is a multiple of its sum of digits (10), and also a Moran number because the ratio is a prime number: 1212121 = 12121210 / (1 + 2 + 1 + 2 + 1 + 2 + 1 + 0).

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (12121211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 606051 + ... + 606070.

Almost surely, 212121210 is an apocalyptic number.

12121210 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

12121210 is a deficient number, since it is larger than the sum of its proper divisors (9696986).

12121210 is a wasteful number, since it uses less digits than its factorization.

12121210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1212128.

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 12121210 is about 3481.5528144780. The cubic root of 12121210 is about 229.7111054611.

12121210 divided by its sum of digits (10) gives a palindrome (1212121).

Adding to 12121210 its reverse (1212121), we get a palindrome (13333331).

The spelling of 12121210 in words is "twelve million, one hundred twenty-one thousand, two hundred ten".

Divisors: 1 2 5 10 1212121 2424242 6060605 12121210