21246520 has 16 divisors (see below), whose sum is σ = 47804760. Its totient is φ = 8498592.

The previous prime is 21246517. The next prime is 21246521. The reversal of 21246520 is 2564212.

It is a super-2 number, since 2×21246520² = 902829224220800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21246491 and 21246500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21246521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 265542 + ... + 265621.

Almost surely, 2^21246520 is an apocalyptic number.

21246520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21246520 is an abundant number, since it is smaller than the sum of its proper divisors (26558240).

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

21246520 is a wasteful number, since it uses less digits than its factorization.

21246520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 531174 (or 531170 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 21246520 is about 4609.3947541950. The cubic root of 21246520 is about 276.9677920039.

The spelling of 21246520 in words is "twenty-one million, two hundred forty-six thousand, five hundred twenty".