21679704 has 64 divisors (see below), whose sum is σ = 62316000. Its totient is φ = 6975360.

The previous prime is 21679687. The next prime is 21679711. The reversal of 21679704 is 40797612.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

21679704 is a modest number, since divided by 79704 gives 216 as remainder.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4534 + ... + 7994.

Almost surely, 2^21679704 is an apocalyptic number.

21679704 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21679704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31158000).

21679704 is an abundant number, since it is smaller than the sum of its proper divisors (40636296).

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

21679704 is a wasteful number, since it uses less digits than its factorization.

21679704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3505 (or 3495 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

The square root of 21679704 is about 4656.1469048989. The cubic root of 21679704 is about 278.8374587987.

The spelling of 21679704 in words is "twenty-one million, six hundred seventy-nine thousand, seven hundred four".