21472644 has 24 divisors (see below), whose sum is σ = 51831360. Its totient is φ = 6910624.

The previous prime is 21472631. The next prime is 21472657. The reversal of 21472644 is 44627412.

It is an interprime number because it is at equal distance from previous prime (21472631) and next prime (21472657).

It is a super-2 number, since 2×21472644² = 922148880701472, which contains 22 as substring.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 30504 + ... + 31199.

It is an arithmetic number, because the mean of its divisors is an integer number (2159640).

Almost surely, 2^21472644 is an apocalyptic number.

It is an amenable number.

21472644 is an abundant number, since it is smaller than the sum of its proper divisors (30358716).

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

21472644 is a wasteful number, since it uses less digits than its factorization.

21472644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61739 (or 61737 counting only the distinct ones).

The product of its digits is 10752, while the sum is 30.

The square root of 21472644 is about 4633.8584354725. The cubic root of 21472644 is about 277.9469042707.

The spelling of 21472644 in words is "twenty-one million, four hundred seventy-two thousand, six hundred forty-four".