20646520 has 16 divisors (see below), whose sum is σ = 46454760. Its totient is φ = 8258592.

The previous prime is 20646511. The next prime is 20646523. The reversal of 20646520 is 2564602.

It is a super-2 number, since 2×20646520² = 852557576220800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20646523) 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, 258042 + ... + 258121.

Almost surely, 2^20646520 is an apocalyptic number.

20646520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20646520 is an abundant number, since it is smaller than the sum of its proper divisors (25808240).

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

20646520 is a wasteful number, since it uses less digits than its factorization.

20646520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 516174 (or 516170 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 20646520 is about 4543.8441874695. The cubic root of 20646520 is about 274.3356746997.

The spelling of 20646520 in words is "twenty million, six hundred forty-six thousand, five hundred twenty".