641795521 has 2 divisors, whose sum is σ = 641795522. Its totient is φ = 641795520.

The previous prime is 641795501. The next prime is 641795537. The reversal of 641795521 is 125597146.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 589955521 + 51840000 = 24289^2 + 7200^2 .

It is a cyclic number.

It is not a de Polignac number, because 641795521 - 2⁵ = 641795489 is a prime.

It is a super-2 number, since 2×641795521² = 823802981551322882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (641795501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320897760 + 320897761.

It is an arithmetic number, because the mean of its divisors is an integer number (320897761).

Almost surely, 2^641795521 is an apocalyptic number.

It is an amenable number.

641795521 is a deficient number, since it is larger than the sum of its proper divisors (1).

641795521 is an equidigital number, since it uses as much as digits as its factorization.

641795521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 75600, while the sum is 40.

The square root of 641795521 is about 25333.6835260883. The cubic root of 641795521 is about 862.5790261834.

The spelling of 641795521 in words is "six hundred forty-one million, seven hundred ninety-five thousand, five hundred twenty-one".