21417872 has 20 divisors (see below), whose sum is σ = 47425536. Its totient is φ = 9179040.

The previous prime is 21417871. The next prime is 21417889. The reversal of 21417872 is 27871412.

It is a happy number.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21417871) 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, 95504 + ... + 95727.

Almost surely, 2^21417872 is an apocalyptic number.

It is an amenable number.

21417872 is an abundant number, since it is smaller than the sum of its proper divisors (26007664).

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

21417872 is a wasteful number, since it uses less digits than its factorization.

21417872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191246 (or 191240 counting only the distinct ones).

The product of its digits is 6272, while the sum is 32.

The square root of 21417872 is about 4627.9446841984. The cubic root of 21417872 is about 277.7103758716.

The spelling of 21417872 in words is "twenty-one million, four hundred seventeen thousand, eight hundred seventy-two".