20513520 has 80 divisors (see below), whose sum is σ = 70665120. Its totient is φ = 5469696.

The previous prime is 20513513. The next prime is 20513531. The reversal of 20513520 is 2531502.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

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 = 20513493 and 20513502.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2589 + ... + 6908.

It is an arithmetic number, because the mean of its divisors is an integer number (883314).

Almost surely, 2^20513520 is an apocalyptic number.

20513520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20513520 is an abundant number, since it is smaller than the sum of its proper divisors (50151600).

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

20513520 is a wasteful number, since it uses less digits than its factorization.

20513520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9519 (or 9507 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 20513520 is about 4529.1853572138. The cubic root of 20513520 is about 273.7453367567.

The spelling of 20513520 in words is "twenty million, five hundred thirteen thousand, five hundred twenty".