123656421 has 32 divisors (see below), whose sum is σ = 191962368. Its totient is φ = 69350400.

The previous prime is 123656387. The next prime is 123656443. The reversal of 123656421 is 124656321.

It is not a de Polignac number, because 123656421 - 2¹⁰ = 123655397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123652421) 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 31 ways as a sum of consecutive naturals, for example, 366765 + ... + 367101.

It is an arithmetic number, because the mean of its divisors is an integer number (5998824).

Almost surely, 2^123656421 is an apocalyptic number.

It is an amenable number.

123656421 is a deficient number, since it is larger than the sum of its proper divisors (68305947).

123656421 is a wasteful number, since it uses less digits than its factorization.

123656421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 621.

The product of its digits is 8640, while the sum is 30.

The square root of 123656421 is about 11120.0908719309. The cubic root of 123656421 is about 498.2021042236.

The spelling of 123656421 in words is "one hundred twenty-three million, six hundred fifty-six thousand, four hundred twenty-one".