21268980 has 120 divisors (see below), whose sum is σ = 70334880. Its totient is φ = 5365440.

The previous prime is 21268967. The next prime is 21268991. The reversal of 21268980 is 8986212.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a zygodrome in base 11.

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 39 ways as a sum of consecutive naturals, for example, 30435 + ... + 31125.

It is an arithmetic number, because the mean of its divisors is an integer number (586124).

Almost surely, 2^21268980 is an apocalyptic number.

21268980 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 21268980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35167440).

21268980 is an abundant number, since it is smaller than the sum of its proper divisors (49065900).

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

21268980 is a wasteful number, since it uses less digits than its factorization.

21268980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 731 (or 720 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 21268980 is about 4611.8304392074. The cubic root of 21268980 is about 277.0653531715.

The spelling of 21268980 in words is "twenty-one million, two hundred sixty-eight thousand, nine hundred eighty".