123256921 has 4 divisors (see below), whose sum is σ = 124073344. Its totient is φ = 122440500.

The previous prime is 123256883. The next prime is 123256927. The reversal of 123256921 is 129652321.

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.

It is a cyclic number.

It is not a de Polignac number, because 123256921 - 2¹³ = 123248729 is a prime.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123256927) 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, 407985 + ... + 408286.

It is an arithmetic number, because the mean of its divisors is an integer number (31018336).

Almost surely, 2^123256921 is an apocalyptic number.

It is an amenable number.

123256921 is a deficient number, since it is larger than the sum of its proper divisors (816423).

123256921 is an equidigital number, since it uses as much as digits as its factorization.

123256921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 816422.

The product of its digits is 6480, while the sum is 31.

The square root of 123256921 is about 11102.1133573748. The cubic root of 123256921 is about 497.6650072589.

The spelling of 123256921 in words is "one hundred twenty-three million, two hundred fifty-six thousand, nine hundred twenty-one".