21612672 has 96 divisors (see below), whose sum is σ = 63289980. Its totient is φ = 7077888.

The previous prime is 21612637. The next prime is 21612677. The reversal of 21612672 is 27621612.

It can be written as a sum of positive squares in 2 ways, for example, as 18870336 + 2742336 = 4344^2 + 1656^2 .

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21612677) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 83968 + ... + 84224.

Almost surely, 2^21612672 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 21612672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31644990).

21612672 is an abundant number, since it is smaller than the sum of its proper divisors (41677308).

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

21612672 is a wasteful number, since it uses less digits than its factorization.

21612672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 350 (or 335 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 21612672 is about 4648.9431056962. The cubic root of 21612672 is about 278.5497806790.

The spelling of 21612672 in words is "twenty-one million, six hundred twelve thousand, six hundred seventy-two".