621656131 has 4 divisors (see below), whose sum is σ = 621706672. Its totient is φ = 621605592.

The previous prime is 621656107. The next prime is 621656137. The reversal of 621656131 is 131656126.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 621656131 - 2⁵ = 621656099 is a prime.

It is a super-2 number, since 2×621656131² = 772912690419778322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 621656093 and 621656102.

It is not an unprimeable number, because it can be changed into a prime (621656137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6466 + ... + 35848.

It is an arithmetic number, because the mean of its divisors is an integer number (155426668).

Almost surely, 2^621656131 is an apocalyptic number.

621656131 is a deficient number, since it is larger than the sum of its proper divisors (50541).

621656131 is a wasteful number, since it uses less digits than its factorization.

621656131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50540.

The product of its digits is 6480, while the sum is 31.

The square root of 621656131 is about 24933.0329282260. The cubic root of 621656131 is about 853.4604631183.

The spelling of 621656131 in words is "six hundred twenty-one million, six hundred fifty-six thousand, one hundred thirty-one".