21478672 has 20 divisors (see below), whose sum is σ = 42584080. Its totient is φ = 10489248.

The previous prime is 21478669. The next prime is 21478679. The reversal of 21478672 is 27687412.

It is a super-2 number, since 2×21478672² = 922666701767168, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21478679) 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, 14922 + ... + 16297.

It is an arithmetic number, because the mean of its divisors is an integer number (2129204).

Almost surely, 2^21478672 is an apocalyptic number.

It is an amenable number.

21478672 is a deficient number, since it is larger than the sum of its proper divisors (21105408).

21478672 is a wasteful number, since it uses less digits than its factorization.

21478672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31270 (or 31264 counting only the distinct ones).

The product of its digits is 37632, while the sum is 37.

The square root of 21478672 is about 4634.5088197133. The cubic root of 21478672 is about 277.9729111158.

The spelling of 21478672 in words is "twenty-one million, four hundred seventy-eight thousand, six hundred seventy-two".