21123964 has 12 divisors (see below), whose sum is σ = 37004800. Its totient is φ = 10551168.

The previous prime is 21123917. The next prime is 21123983. The reversal of 21123964 is 46932112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3052 + ... + 7180.

Almost surely, 2^21123964 is an apocalyptic number.

It is an amenable number.

21123964 is a deficient number, since it is larger than the sum of its proper divisors (15880836).

21123964 is a wasteful number, since it uses less digits than its factorization.

21123964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5412 (or 5410 counting only the distinct ones).

The product of its digits is 2592, while the sum is 28.

The square root of 21123964 is about 4596.0813743884. The cubic root of 21123964 is about 276.4342216273.

The spelling of 21123964 in words is "twenty-one million, one hundred twenty-three thousand, nine hundred sixty-four".