21076720 has 80 divisors (see below), whose sum is σ = 57014208. Its totient is φ = 7096320.

The previous prime is 21076711. The next prime is 21076739. The reversal of 21076720 is 2767012.

It is a tau number, because it is divible by the number of its divisors (80).

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 15 ways as a sum of consecutive naturals, for example, 33852 + ... + 34468.

Almost surely, 2^21076720 is an apocalyptic number.

21076720 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 21076720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28507104).

21076720 is an abundant number, since it is smaller than the sum of its proper divisors (35937488).

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

21076720 is a wasteful number, since it uses less digits than its factorization.

21076720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 698 (or 692 counting only the distinct ones).

The product of its (nonzero) digits is 1176, while the sum is 25.

The square root of 21076720 is about 4590.9389017934. The cubic root of 21076720 is about 276.2279849781.

The spelling of 21076720 in words is "twenty-one million, seventy-six thousand, seven hundred twenty".