21570757672 has 8 divisors (see below), whose sum is σ = 40445170650. Its totient is φ = 10785378832.

The previous prime is 21570757657. The next prime is 21570757679. The reversal of 21570757672 is 27675707512.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20965302436 + 605455236 = 144794^2 + 24606^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21570757679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1348172347 + ... + 1348172362.

Almost surely, 2^21570757672 is an apocalyptic number.

It is an amenable number.

21570757672 is a deficient number, since it is larger than the sum of its proper divisors (18874412978).

21570757672 is a wasteful number, since it uses less digits than its factorization.

21570757672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2696344715 (or 2696344711 counting only the distinct ones).

The product of its (nonzero) digits is 1440600, while the sum is 49.

The spelling of 21570757672 in words is "twenty-one billion, five hundred seventy million, seven hundred fifty-seven thousand, six hundred seventy-two".