20013621 has 16 divisors (see below), whose sum is σ = 27156480. Its totient is φ = 13109040.

The previous prime is 20013613. The next prime is 20013659. The reversal of 20013621 is 12631002.

It is not a de Polignac number, because 20013621 - 2³ = 20013613 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20013621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20013671) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 73716 + ... + 73986.

It is an arithmetic number, because the mean of its divisors is an integer number (1697280).

Almost surely, 2^20013621 is an apocalyptic number.

It is an amenable number.

20013621 is a deficient number, since it is larger than the sum of its proper divisors (7142859).

20013621 is a wasteful number, since it uses less digits than its factorization.

20013621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 616.

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 20013621 is about 4473.6585698956. The cubic root of 20013621 is about 271.5033694795.

Adding to 20013621 its reverse (12631002), we get a palindrome (32644623).

The spelling of 20013621 in words is "twenty million, thirteen thousand, six hundred twenty-one".