21271147972 has 6 divisors (see below), whose sum is σ = 37224508958. Its totient is φ = 10635573984.

The previous prime is 21271147951. The next prime is 21271147973. The reversal of 21271147972 is 27974117212.

It can be written as a sum of positive squares in only one way, i.e., 11360149056 + 9910998916 = 106584^2 + 99554^2 .

It is not an unprimeable number, because it can be changed into a prime (21271147973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2658893493 + ... + 2658893500.

Almost surely, 2^21271147972 is an apocalyptic number.

It is an amenable number.

21271147972 is a deficient number, since it is larger than the sum of its proper divisors (15953360986).

21271147972 is a wasteful number, since it uses less digits than its factorization.

21271147972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5317786997 (or 5317786995 counting only the distinct ones).

The product of its digits is 98784, while the sum is 43.

The spelling of 21271147972 in words is "twenty-one billion, two hundred seventy-one million, one hundred forty-seven thousand, nine hundred seventy-two".