21417880 has 32 divisors (see below), whose sum is σ = 52572240. Its totient is φ = 7788160.

The previous prime is 21417871. The next prime is 21417889. The reversal of 21417880 is 8871412.

It is an interprime number because it is at equal distance from previous prime (21417871) and next prime (21417889).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21417889) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23899 + ... + 24778.

Almost surely, 2^21417880 is an apocalyptic number.

21417880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21417880 is an abundant number, since it is smaller than the sum of its proper divisors (31154360).

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

21417880 is a wasteful number, since it uses less digits than its factorization.

21417880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48699 (or 48695 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 31.

The square root of 21417880 is about 4627.9455485129. The cubic root of 21417880 is about 277.7104104484.

The spelling of 21417880 in words is "twenty-one million, four hundred seventeen thousand, eight hundred eighty".