21397704 has 16 divisors (see below), whose sum is σ = 53494320. Its totient is φ = 7132560.

The previous prime is 21397699. The next prime is 21397711. The reversal of 21397704 is 40779312.

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, 445762 + ... + 445809.

It is an arithmetic number, because the mean of its divisors is an integer number (3343395).

Almost surely, 2^21397704 is an apocalyptic number.

21397704 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21397704 is an abundant number, since it is smaller than the sum of its proper divisors (32096616).

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

21397704 is a wasteful number, since it uses less digits than its factorization.

21397704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 891580 (or 891576 counting only the distinct ones).

The product of its (nonzero) digits is 10584, while the sum is 33.

The square root of 21397704 is about 4625.7652339910. The cubic root of 21397704 is about 277.6231804399.

The spelling of 21397704 in words is "twenty-one million, three hundred ninety-seven thousand, seven hundred four".