21479920 has 120 divisors (see below), whose sum is σ = 62933472. Its totient is φ = 6673920.

The previous prime is 21479917. The next prime is 21479957. The reversal of 21479920 is 2997412.

It is a happy number.

It is a super-2 number, since 2×21479920² = 922773926412800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 67602 + ... + 67918.

Almost surely, 2^21479920 is an apocalyptic number.

21479920 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 21479920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31466736).

21479920 is an abundant number, since it is smaller than the sum of its proper divisors (41453552).

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

21479920 is a wasteful number, since it uses less digits than its factorization.

21479920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 359 (or 342 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 21479920 is about 4634.6434598575. The cubic root of 21479920 is about 277.9782948049.

The spelling of 21479920 in words is "twenty-one million, four hundred seventy-nine thousand, nine hundred twenty".