20621031 has 16 divisors (see below), whose sum is σ = 28235520. Its totient is φ = 13381760.

The previous prime is 20621009. The next prime is 20621063. The reversal of 20621031 is 13012602.

It is a cyclic number.

It is not a de Polignac number, because 20621031 - 2²² = 16426727 is a prime.

It is a super-2 number, since 2×20621031² = 850453839005922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20621031.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20621071) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19486 + ... + 20516.

It is an arithmetic number, because the mean of its divisors is an integer number (1764720).

Almost surely, 2^20621031 is an apocalyptic number.

20621031 is a deficient number, since it is larger than the sum of its proper divisors (7614489).

20621031 is a wasteful number, since it uses less digits than its factorization.

20621031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1206.

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

The square root of 20621031 is about 4541.0385376035. The cubic root of 20621031 is about 274.2227352226. Note that the first 3 decimals are identical.

Adding to 20621031 its reverse (13012602), we get a palindrome (33633633).

The spelling of 20621031 in words is "twenty million, six hundred twenty-one thousand, thirty-one".