20213520 has 40 divisors (see below), whose sum is σ = 62662656. Its totient is φ = 5390208.

The previous prime is 20213503. The next prime is 20213563. The reversal of 20213520 is 2531202.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 20213520.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41872 + ... + 42351.

Almost surely, 2^20213520 is an apocalyptic number.

20213520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20213520 is an abundant number, since it is smaller than the sum of its proper divisors (42449136).

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

20213520 is a wasteful number, since it uses less digits than its factorization.

20213520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84239 (or 84233 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 20213520 is about 4495.9448395193. The cubic root of 20213520 is about 272.4043150854.

Adding to 20213520 its reverse (2531202), we get a palindrome (22744722).

The spelling of 20213520 in words is "twenty million, two hundred thirteen thousand, five hundred twenty".