21052520 has 32 divisors (see below), whose sum is σ = 47562120. Its totient is φ = 8386560.

The previous prime is 21052489. The next prime is 21052547. The reversal of 21052520 is 2525012.

It can be written as a sum of positive squares in 4 ways, for example, as 12630916 + 8421604 = 3554^2 + 2902^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10304 + ... + 12176.

Almost surely, 2^21052520 is an apocalyptic number.

21052520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21052520 is an abundant number, since it is smaller than the sum of its proper divisors (26509600).

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

21052520 is a wasteful number, since it uses less digits than its factorization.

21052520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2165 (or 2161 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 17.

The square root of 21052520 is about 4588.3025183612. The cubic root of 21052520 is about 276.1222240990.

Adding to 21052520 its reverse (2525012), we get a palindrome (23577532).

The spelling of 21052520 in words is "twenty-one million, fifty-two thousand, five hundred twenty".