21536980 has 48 divisors (see below), whose sum is σ = 47013120. Its totient is φ = 8281728.

The previous prime is 21536953. The next prime is 21536989. The reversal of 21536980 is 8963512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21536989) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67782 + ... + 68098.

It is an arithmetic number, because the mean of its divisors is an integer number (979440).

Almost surely, 2^21536980 is an apocalyptic number.

21536980 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 21536980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23506560).

21536980 is an abundant number, since it is smaller than the sum of its proper divisors (25476140).

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

21536980 is a wasteful number, since it uses less digits than its factorization.

21536980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 448 (or 446 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 21536980 is about 4640.7951904819. The cubic root of 21536980 is about 278.2242208796.

It can be divided in two parts, 2 and 1536980, that multiplied together give a triangular number (3073960 = T₂₄₇₉).

The spelling of 21536980 in words is "twenty-one million, five hundred thirty-six thousand, nine hundred eighty".