21316938 has 16 divisors (see below), whose sum is σ = 43333536. Its totient is φ = 6989040.

The previous prime is 21316903. The next prime is 21316987. The reversal of 21316938 is 83961312.

It is a junction number, because it is equal to n+sod(n) for n = 21316899 and 21316908.

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, 28756 + ... + 29487.

It is an arithmetic number, because the mean of its divisors is an integer number (2708346).

Almost surely, 2^21316938 is an apocalyptic number.

21316938 is an abundant number, since it is smaller than the sum of its proper divisors (22016598).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21316938 is a wasteful number, since it uses less digits than its factorization.

21316938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58309.

The product of its digits is 7776, while the sum is 33.

The square root of 21316938 is about 4617.0269654833. The cubic root of 21316938 is about 277.2734422237.

The spelling of 21316938 in words is "twenty-one million, three hundred sixteen thousand, nine hundred thirty-eight".