21364980 has 216 divisors, whose sum is σ = 77105952. Its totient is φ = 4402944.

The previous prime is 21364951. The next prime is 21364991. The reversal of 21364980 is 8946312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 496839 + ... + 496881.

It is an arithmetic number, because the mean of its divisors is an integer number (356972).

Almost surely, 2^21364980 is an apocalyptic number.

21364980 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 21364980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38552976).

21364980 is an abundant number, since it is smaller than the sum of its proper divisors (55740972).

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

21364980 is a wasteful number, since it uses less digits than its factorization.

21364980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95 (or 73 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 21364980 is about 4622.2267361089. The cubic root of 21364980 is about 277.4815830647.

The spelling of 21364980 in words is "twenty-one million, three hundred sixty-four thousand, nine hundred eighty".