123990921 has 24 divisors (see below), whose sum is σ = 187911360. Its totient is φ = 78674400.

The previous prime is 123990913. The next prime is 123990931. The reversal of 123990921 is 129099321.

It is a happy number.

It is not a de Polignac number, because 123990921 - 2³ = 123990913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (123990931) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15186 + ... + 21876.

It is an arithmetic number, because the mean of its divisors is an integer number (7829640).

Almost surely, 2^123990921 is an apocalyptic number.

It is an amenable number.

123990921 is a deficient number, since it is larger than the sum of its proper divisors (63920439).

123990921 is a wasteful number, since it uses less digits than its factorization.

123990921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6797 (or 6794 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 123990921 is about 11135.1210590635. The cubic root of 123990921 is about 498.6509245982.

The spelling of 123990921 in words is "one hundred twenty-three million, nine hundred ninety thousand, nine hundred twenty-one".