621347681 has 2 divisors, whose sum is σ = 621347682. Its totient is φ = 621347680.

The previous prime is 621347677. The next prime is 621347689. The reversal of 621347681 is 186743126.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 536339281 + 85008400 = 23159^2 + 9220^2 .

It is a cyclic number.

It is not a de Polignac number, because 621347681 - 2² = 621347677 is a prime.

It is a super-2 number, since 2×621347681² = 772145881368155522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (621347689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310673840 + 310673841.

It is an arithmetic number, because the mean of its divisors is an integer number (310673841).

Almost surely, 2^621347681 is an apocalyptic number.

It is an amenable number.

621347681 is a deficient number, since it is larger than the sum of its proper divisors (1).

621347681 is an equidigital number, since it uses as much as digits as its factorization.

621347681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 38.

The square root of 621347681 is about 24926.8465915767. The cubic root of 621347681 is about 853.3192846232.

The spelling of 621347681 in words is "six hundred twenty-one million, three hundred forty-seven thousand, six hundred eighty-one".