21275120 has 40 divisors (see below), whose sum is σ = 50156016. Its totient is φ = 8391168.

The previous prime is 21275099. The next prime is 21275123. The reversal of 21275120 is 2157212.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21275092 and 21275101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21275123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4019 + ... + 7661.

Almost surely, 2^21275120 is an apocalyptic number.

21275120 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 21275120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25078008).

21275120 is an abundant number, since it is smaller than the sum of its proper divisors (28880896).

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

21275120 is a wasteful number, since it uses less digits than its factorization.

21275120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3729 (or 3723 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 21275120 is about 4612.4960704590. The cubic root of 21275120 is about 277.0920119894.

The spelling of 21275120 in words is "twenty-one million, two hundred seventy-five thousand, one hundred twenty".