21204647431 has 16 divisors (see below), whose sum is σ = 24322327200. Its totient is φ = 18307094400.

The previous prime is 21204647407. The next prime is 21204647437. The reversal of 21204647431 is 13474640212.

It is a cyclic number.

It is not a de Polignac number, because 21204647431 - 2⁹ = 21204646919 is a prime.

It is a super-2 number, since 2×21204647431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21204647437) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 525396 + ... + 564313.

It is an arithmetic number, because the mean of its divisors is an integer number (1520145450).

Almost surely, 2^21204647431 is an apocalyptic number.

21204647431 is a deficient number, since it is larger than the sum of its proper divisors (3117679769).

21204647431 is a wasteful number, since it uses less digits than its factorization.

21204647431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1089810.

The product of its (nonzero) digits is 32256, while the sum is 34.

The spelling of 21204647431 in words is "twenty-one billion, two hundred four million, six hundred forty-seven thousand, four hundred thirty-one".