21276720 has 120 divisors (see below), whose sum is σ = 73990800. Its totient is φ = 5472768.

The previous prime is 21276683. The next prime is 21276727. The reversal of 21276720 is 2767212.

It is a tau number, because it is divible by the number of its divisors (120).

It is not an unprimeable number, because it can be changed into a prime (21276727) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20371 + ... + 21389.

It is an arithmetic number, because the mean of its divisors is an integer number (616590).

Almost surely, 2^21276720 is an apocalyptic number.

21276720 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 21276720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36995400).

21276720 is an abundant number, since it is smaller than the sum of its proper divisors (52714080).

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

21276720 is a wasteful number, since it uses less digits than its factorization.

21276720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1067 (or 1058 counting only the distinct ones).

The product of its (nonzero) digits is 2352, while the sum is 27.

The square root of 21276720 is about 4612.6695090804. The cubic root of 21276720 is about 277.0989580702.

The spelling of 21276720 in words is "twenty-one million, two hundred seventy-six thousand, seven hundred twenty".