21351704 has 16 divisors (see below), whose sum is σ = 43674120. Its totient is φ = 9705280.

The previous prime is 21351679. The next prime is 21351709. The reversal of 21351704 is 40715312.

It is a self number, because there is not a number n which added to its sum of digits gives 21351704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21351709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121229 + ... + 121404.

Almost surely, 2^21351704 is an apocalyptic number.

It is an amenable number.

21351704 is an abundant number, since it is smaller than the sum of its proper divisors (22322416).

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

21351704 is a wasteful number, since it uses less digits than its factorization.

21351704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242650 (or 242646 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 21351704 is about 4620.7904085773. The cubic root of 21351704 is about 277.4240963303.

The spelling of 21351704 in words is "twenty-one million, three hundred fifty-one thousand, seven hundred four".