21972672 has 84 divisors (see below), whose sum is σ = 64745616. Its totient is φ = 7119360.

The previous prime is 21972667. The next prime is 21972677. The reversal of 21972672 is 27627912.

It is an interprime number because it is at equal distance from previous prime (21972667) and next prime (21972677).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21972677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20797 + ... + 21827.

Almost surely, 2^21972672 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21972672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32372808).

21972672 is an abundant number, since it is smaller than the sum of its proper divisors (42772944).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21972672 is a wasteful number, since it uses less digits than its factorization.

21972672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1086 (or 1073 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The square root of 21972672 is about 4687.5016799997. The cubic root of 21972672 is about 280.0878635821.

The spelling of 21972672 in words is "twenty-one million, nine hundred seventy-two thousand, six hundred seventy-two".