21396980 has 24 divisors (see below), whose sum is σ = 49019040. Its totient is φ = 7780640.

The previous prime is 21396967. The next prime is 21397007. The reversal of 21396980 is 8969312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48410 + ... + 48849.

It is an arithmetic number, because the mean of its divisors is an integer number (2042460).

Almost surely, 2^21396980 is an apocalyptic number.

21396980 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21396980 is an abundant number, since it is smaller than the sum of its proper divisors (27622060).

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

21396980 is a wasteful number, since it uses less digits than its factorization.

21396980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97279 (or 97277 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 21396980 is about 4625.6869760069. The cubic root of 21396980 is about 277.6200492403.

It can be divided in two parts, 2139 and 6980, that added together give a palindrome (9119).

The spelling of 21396980 in words is "twenty-one million, three hundred ninety-six thousand, nine hundred eighty".