21079872 has 112 divisors (see below), whose sum is σ = 67665600. Its totient is φ = 6382080.

The previous prime is 21079867. The next prime is 21079879. The reversal of 21079872 is 27897012.

It is a super-2 number, since 2×21079872² = 888722007072768, 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 (21079879) 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, 18454 + ... + 19562.

Almost surely, 2^21079872 is an apocalyptic number.

21079872 is a gapful number since it is divisible by the number (22) 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 21079872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33832800).

21079872 is an abundant number, since it is smaller than the sum of its proper divisors (46585728).

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

21079872 is a wasteful number, since it uses less digits than its factorization.

21079872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1141 (or 1125 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 21079872 is about 4591.2821738595. The cubic root of 21079872 is about 276.2417541542.

The spelling of 21079872 in words is "twenty-one million, seventy-nine thousand, eight hundred seventy-two".