621621137 has 2 divisors, whose sum is σ = 621621138. Its totient is φ = 621621136.

The previous prime is 621621079. The next prime is 621621139. The reversal of 621621137 is 731126126.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 605947456 + 15673681 = 24616^2 + 3959^2 .

It is a cyclic number.

It is not a de Polignac number, because 621621137 - 2⁶ = 621621073 is a prime.

Together with 621621139, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (621621139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310810568 + 310810569.

It is an arithmetic number, because the mean of its divisors is an integer number (310810569).

Almost surely, 2^621621137 is an apocalyptic number.

It is an amenable number.

621621137 is a deficient number, since it is larger than the sum of its proper divisors (1).

621621137 is an equidigital number, since it uses as much as digits as its factorization.

621621137 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 29.

The square root of 621621137 is about 24932.3311585580. The cubic root of 621621137 is about 853.4444486078. Note that the first 5 decimals are identical.

The spelling of 621621137 in words is "six hundred twenty-one million, six hundred twenty-one thousand, one hundred thirty-seven".