21712896 has 156 divisors (see below), whose sum is σ = 68149120. Its totient is φ = 6635520.

The previous prime is 21712871. The next prime is 21712907. The reversal of 21712896 is 69821712.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21712896.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 700401 + ... + 700431.

Almost surely, 2^21712896 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 21712896, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34074560).

21712896 is an abundant number, since it is smaller than the sum of its proper divisors (46436224).

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

21712896 is a wasteful number, since it uses less digits than its factorization.

21712896 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80 (or 55 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 21712896 is about 4659.7098622125. The cubic root of 21712896 is about 278.9796878880.

The spelling of 21712896 in words is "twenty-one million, seven hundred twelve thousand, eight hundred ninety-six".