21365032168 has 8 divisors (see below), whose sum is σ = 40059435330. Its totient is φ = 10682516080.

The previous prime is 21365032127. The next prime is 21365032181. The reversal of 21365032168 is 86123056312.

It can be written as a sum of positive squares in only one way, i.e., 21072006244 + 293025924 = 145162^2 + 17118^2 .

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

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1335314503 + ... + 1335314518.

Almost surely, 2^21365032168 is an apocalyptic number.

It is an amenable number.

21365032168 is a deficient number, since it is larger than the sum of its proper divisors (18694403162).

21365032168 is a wasteful number, since it uses less digits than its factorization.

21365032168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2670629027 (or 2670629023 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 37.

The spelling of 21365032168 in words is "twenty-one billion, three hundred sixty-five million, thirty-two thousand, one hundred sixty-eight".