21972116128 has 12 divisors (see below), whose sum is σ = 43257603690. Its totient is φ = 10986058048.

The previous prime is 21972116119. The next prime is 21972116129. The reversal of 21972116128 is 82161127912.

It can be written as a sum of positive squares in only one way, i.e., 17300667024 + 4671449104 = 131532^2 + 68348^2 .

It is not an unprimeable number, because it can be changed into a prime (21972116129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343314283 + ... + 343314346.

Almost surely, 2^21972116128 is an apocalyptic number.

It is an amenable number.

21972116128 is a deficient number, since it is larger than the sum of its proper divisors (21285487562).

21972116128 is an equidigital number, since it uses as much as digits as its factorization.

21972116128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 686628639 (or 686628631 counting only the distinct ones).

The product of its digits is 24192, while the sum is 40.

The spelling of 21972116128 in words is "twenty-one billion, nine hundred seventy-two million, one hundred sixteen thousand, one hundred twenty-eight".