21691704 has 32 divisors (see below), whose sum is σ = 55152000. Its totient is φ = 7107552.

The previous prime is 21691693. The next prime is 21691721. The reversal of 21691704 is 40719612.

It is a happy number.

It is a congruent number.

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, 6244 + ... + 9075.

It is an arithmetic number, because the mean of its divisors is an integer number (1723500).

Almost surely, 2^21691704 is an apocalyptic number.

21691704 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21691704 is an abundant number, since it is smaller than the sum of its proper divisors (33460296).

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

21691704 is a wasteful number, since it uses less digits than its factorization.

21691704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15387 (or 15383 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 21691704 is about 4657.4353457670. The cubic root of 21691704 is about 278.8888960375. Note that the first 4 decimals are identical.

The spelling of 21691704 in words is "twenty-one million, six hundred ninety-one thousand, seven hundred four".