21358680 has 128 divisors (see below), whose sum is σ = 74926080. Its totient is φ = 4769280.

The previous prime is 21358669. The next prime is 21358691. The reversal of 21358680 is 8685312.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21358669) and next prime (21358691).

It is a super-2 number, since 2×21358680² = 912386422684800, which contains 22 as substring.

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 39210 + ... + 39750.

It is an arithmetic number, because the mean of its divisors is an integer number (585360).

Almost surely, 2^21358680 is an apocalyptic number.

21358680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21358680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37463040).

21358680 is an abundant number, since it is smaller than the sum of its proper divisors (53567400).

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

21358680 is a wasteful number, since it uses less digits than its factorization.

21358680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 609 (or 605 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 21358680 is about 4621.5451961438. The cubic root of 21358680 is about 277.4543062496.

The spelling of 21358680 in words is "twenty-one million, three hundred fifty-eight thousand, six hundred eighty".