21069520 has 20 divisors (see below), whose sum is σ = 48986820. Its totient is φ = 8427776.

The previous prime is 21069487. The next prime is 21069547. The reversal of 21069520 is 2596012.

It can be written as a sum of positive squares in 2 ways, for example, as 15649936 + 5419584 = 3956^2 + 2328^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131605 + ... + 131764.

It is an arithmetic number, because the mean of its divisors is an integer number (2449341).

Almost surely, 2^21069520 is an apocalyptic number.

21069520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21069520 is an abundant number, since it is smaller than the sum of its proper divisors (27917300).

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

21069520 is a wasteful number, since it uses less digits than its factorization.

21069520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263382 (or 263376 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 21069520 is about 4590.1546814895. The cubic root of 21069520 is about 276.1965273951.

The spelling of 21069520 in words is "twenty-one million, sixty-nine thousand, five hundred twenty".