21513120 has 48 divisors (see below), whose sum is σ = 67767840. Its totient is φ = 5736704.

The previous prime is 21513113. The next prime is 21513127. The reversal of 21513120 is 2131512.

It is an interprime number because it is at equal distance from previous prime (21513113) and next prime (21513127).

It is a tau number, because it is divible by the number of its divisors (48).

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 21513120.

It is not an unprimeable number, because it can be changed into a prime (21513127) 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, 21930 + ... + 22889.

It is an arithmetic number, because the mean of its divisors is an integer number (1411830).

Almost surely, 2^21513120 is an apocalyptic number.

21513120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21513120 is an abundant number, since it is smaller than the sum of its proper divisors (46254720).

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

21513120 is a wasteful number, since it uses less digits than its factorization.

21513120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44837 (or 44829 counting only the distinct ones).

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

The square root of 21513120 is about 4638.2237979640. The cubic root of 21513120 is about 278.1214382408.

Adding to 21513120 its reverse (2131512), we get a palindrome (23644632).

The spelling of 21513120 in words is "twenty-one million, five hundred thirteen thousand, one hundred twenty".