123320021 has 4 divisors (see below), whose sum is σ = 134530944. Its totient is φ = 112109100.

The previous prime is 123320003. The next prime is 123320033. The reversal of 123320021 is 120023321.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 120023321 = 11 ⋅10911211.

It is a cyclic number.

It is not a de Polignac number, because 123320021 - 2⁶ = 123319957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 123319978 and 123320005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123320221) 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, 5605445 + ... + 5605466.

It is an arithmetic number, because the mean of its divisors is an integer number (33632736).

Almost surely, 2^123320021 is an apocalyptic number.

123320021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

123320021 is a deficient number, since it is larger than the sum of its proper divisors (11210923).

123320021 is a wasteful number, since it uses less digits than its factorization.

123320021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11210922.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 123320021 is about 11104.9547950453. The cubic root of 123320021 is about 497.7499174462.

Adding to 123320021 its reverse (120023321), we get a palindrome (243343342).

The spelling of 123320021 in words is "one hundred twenty-three million, three hundred twenty thousand, twenty-one".