21271972 has 12 divisors (see below), whose sum is σ = 37588096. Its totient is φ = 10532520.

The previous prime is 21271969. The next prime is 21271973. The reversal of 21271972 is 27917212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21271973) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25404 + ... + 26227.

Almost surely, 2^21271972 is an apocalyptic number.

It is an amenable number.

21271972 is a deficient number, since it is larger than the sum of its proper divisors (16316124).

21271972 is a wasteful number, since it uses less digits than its factorization.

21271972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51738 (or 51736 counting only the distinct ones).

The product of its digits is 3528, while the sum is 31.

The square root of 21271972 is about 4612.1548109317. The cubic root of 21271972 is about 277.0783445588.

The spelling of 21271972 in words is "twenty-one million, two hundred seventy-one thousand, nine hundred seventy-two".