21315120 has 40 divisors (see below), whose sum is σ = 66077616. Its totient is φ = 5683968.

The previous prime is 21315109. The next prime is 21315137. The reversal of 21315120 is 2151312.

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

It is a super-2 number, since 2×21315120² = 908668681228800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21315120.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44167 + ... + 44646.

Almost surely, 2^21315120 is an apocalyptic number.

21315120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21315120 is an abundant number, since it is smaller than the sum of its proper divisors (44762496).

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

21315120 is a wasteful number, since it uses less digits than its factorization.

21315120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88829 (or 88823 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 21315120 is about 4616.8300813437. The cubic root of 21315120 is about 277.2655596430.

Adding to 21315120 its reverse (2151312), we get a palindrome (23466432).

The spelling of 21315120 in words is "twenty-one million, three hundred fifteen thousand, one hundred twenty".