21145684264 has 8 divisors (see below), whose sum is σ = 39648158010. Its totient is φ = 10572842128.

The previous prime is 21145684249. The next prime is 21145684279. The reversal of 21145684264 is 46248654112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21145684249) and next prime (21145684279).

It can be written as a sum of positive squares in only one way, i.e., 14754960900 + 6390723364 = 121470^2 + 79942^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 21145684264.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1321605259 + ... + 1321605274.

Almost surely, 2^21145684264 is an apocalyptic number.

It is an amenable number.

21145684264 is a deficient number, since it is larger than the sum of its proper divisors (18502473746).

21145684264 is a wasteful number, since it uses less digits than its factorization.

21145684264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2643210539 (or 2643210535 counting only the distinct ones).

The product of its digits is 368640, while the sum is 43.

The spelling of 21145684264 in words is "twenty-one billion, one hundred forty-five million, six hundred eighty-four thousand, two hundred sixty-four".