21464640772 has 6 divisors (see below), whose sum is σ = 37563121358. Its totient is φ = 10732320384.

The previous prime is 21464640767. The next prime is 21464640781. The reversal of 21464640772 is 27704646412.

It can be written as a sum of positive squares in only one way, i.e., 12114524356 + 9350116416 = 110066^2 + 96696^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2683080093 + ... + 2683080100.

Almost surely, 2^21464640772 is an apocalyptic number.

It is an amenable number.

21464640772 is a deficient number, since it is larger than the sum of its proper divisors (16098480586).

21464640772 is a wasteful number, since it uses less digits than its factorization.

21464640772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5366160197 (or 5366160195 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 43.

The spelling of 21464640772 in words is "twenty-one billion, four hundred sixty-four million, six hundred forty thousand, seven hundred seventy-two".