621656137 has 2 divisors, whose sum is σ = 621656138. Its totient is φ = 621656136.

The previous prime is 621656107. The next prime is 621656159. The reversal of 621656137 is 731656126.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 330476041 + 291180096 = 18179^2 + 17064^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-621656137 is a prime.

It is equal to p_32395195 and since 621656137 and 32395195 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 621656096 and 621656105.

It is not a weakly prime, because it can be changed into another prime (621656107) 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 as a sum of consecutive naturals, namely, 310828068 + 310828069.

It is an arithmetic number, because the mean of its divisors is an integer number (310828069).

Almost surely, 2^621656137 is an apocalyptic number.

It is an amenable number.

621656137 is a deficient number, since it is larger than the sum of its proper divisors (1).

621656137 is an equidigital number, since it uses as much as digits as its factorization.

621656137 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45360, while the sum is 37.

The square root of 621656137 is about 24933.0330485483. The cubic root of 621656137 is about 853.4604658641.

The spelling of 621656137 in words is "six hundred twenty-one million, six hundred fifty-six thousand, one hundred thirty-seven".