21039120 has 60 divisors (see below), whose sum is σ = 70658796. Its totient is φ = 5610240.

The previous prime is 21039119. The next prime is 21039133. The reversal of 21039120 is 2193012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 3196944 + 17842176 = 1788^2 + 4224^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21039093 and 21039102.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13891 + ... + 15330.

Almost surely, 2^21039120 is an apocalyptic number.

21039120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21039120 is an abundant number, since it is smaller than the sum of its proper divisors (49619676).

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

21039120 is a wasteful number, since it uses less digits than its factorization.

21039120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29240 (or 29231 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 21039120 is about 4586.8420509104. The cubic root of 21039120 is about 276.0636274226.

The spelling of 21039120 in words is "twenty-one million, thirty-nine thousand, one hundred twenty".