621645197 has 2 divisors, whose sum is σ = 621645198. Its totient is φ = 621645196.

The previous prime is 621645191. The next prime is 621645253. The reversal of 621645197 is 791546126.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 499343716 + 122301481 = 22346^2 + 11059^2 .

It is a cyclic number.

It is not a de Polignac number, because 621645197 - 2⁸ = 621644941 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (621645191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310822598 + 310822599.

It is an arithmetic number, because the mean of its divisors is an integer number (310822599).

Almost surely, 2^621645197 is an apocalyptic number.

It is an amenable number.

621645197 is a deficient number, since it is larger than the sum of its proper divisors (1).

621645197 is an equidigital number, since it uses as much as digits as its factorization.

621645197 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 41.

The square root of 621645197 is about 24932.8136599141. The cubic root of 621645197 is about 853.4554593920.

The spelling of 621645197 in words is "six hundred twenty-one million, six hundred forty-five thousand, one hundred ninety-seven".