21388974 has 16 divisors (see below), whose sum is σ = 43773312. Its totient is φ = 6963768.

The previous prime is 21388973. The next prime is 21388981. The reversal of 21388974 is 47988312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21388973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41194 + ... + 41709.

It is an arithmetic number, because the mean of its divisors is an integer number (2735832).

Almost surely, 2^21388974 is an apocalyptic number.

21388974 is an abundant number, since it is smaller than the sum of its proper divisors (22384338).

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

21388974 is a wasteful number, since it uses less digits than its factorization.

21388974 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82951.

The product of its digits is 96768, while the sum is 42.

The square root of 21388974 is about 4624.8215100693. The cubic root of 21388974 is about 277.5854196901.

The spelling of 21388974 in words is "twenty-one million, three hundred eighty-eight thousand, nine hundred seventy-four".