21127920 has 160 divisors (see below), whose sum is σ = 73281024. Its totient is φ = 4992000.

The previous prime is 21127913. The next prime is 21127927. The reversal of 21127920 is 2972112.

It is an interprime number because it is at equal distance from previous prime (21127913) and next prime (21127927).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21127927) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 139845 + ... + 139995.

Almost surely, 2^21127920 is an apocalyptic number.

21127920 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 21127920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36640512).

21127920 is an abundant number, since it is smaller than the sum of its proper divisors (52153104).

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

21127920 is a wasteful number, since it uses less digits than its factorization.

21127920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231 (or 225 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 21127920 is about 4596.5117208596. The cubic root of 21127920 is about 276.4514769985.

The spelling of 21127920 in words is "twenty-one million, one hundred twenty-seven thousand, nine hundred twenty".