21393938 has 16 divisors (see below), whose sum is σ = 33324480. Its totient is φ = 10288656.

The previous prime is 21393929. The next prime is 21393949. The reversal of 21393938 is 83939312.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19595 + ... + 20657.

It is an arithmetic number, because the mean of its divisors is an integer number (2082780).

Almost surely, 2^21393938 is an apocalyptic number.

21393938 is a deficient number, since it is larger than the sum of its proper divisors (11930542).

21393938 is a wasteful number, since it uses less digits than its factorization.

21393938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1441.

The product of its digits is 34992, while the sum is 38.

The square root of 21393938 is about 4625.3581482951. The cubic root of 21393938 is about 277.6068922400.

The spelling of 21393938 in words is "twenty-one million, three hundred ninety-three thousand, nine hundred thirty-eight".