21133980 has 96 divisors (see below), whose sum is σ = 75156480. Its totient is φ = 4829760.

The previous prime is 21133979. The next prime is 21134021. The reversal of 21133980 is 8933112.

It is a super-2 number, since 2×21133980² = 893290221280800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 985 + ... + 6575.

It is an arithmetic number, because the mean of its divisors is an integer number (782880).

Almost surely, 2^21133980 is an apocalyptic number.

21133980 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 21133980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37578240).

21133980 is an abundant number, since it is smaller than the sum of its proper divisors (54022500).

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

21133980 is a wasteful number, since it uses less digits than its factorization.

21133980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5616 (or 5608 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 21133980 is about 4597.1708691324. The cubic root of 21133980 is about 276.4779054686.

It can be divided in two parts, 211 and 33980, that added together give a triangular number (34191 = T₂₆₁).

The spelling of 21133980 in words is "twenty-one million, one hundred thirty-three thousand, nine hundred eighty".