21069792 has 72 divisors (see below), whose sum is σ = 60442200. Its totient is φ = 6961920.

The previous prime is 21069791. The next prime is 21069833. The reversal of 21069792 is 29796012.

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×21069792² = 887872269846528, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21069791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42667 + ... + 43157.

It is an arithmetic number, because the mean of its divisors is an integer number (839475).

Almost surely, 2^21069792 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21069792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30221100).

21069792 is an abundant number, since it is smaller than the sum of its proper divisors (39372408).

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

21069792 is a wasteful number, since it uses less digits than its factorization.

21069792 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 656 (or 645 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The square root of 21069792 is about 4590.1843100250. The cubic root of 21069792 is about 276.1977159229.

The spelling of 21069792 in words is "twenty-one million, sixty-nine thousand, seven hundred ninety-two".