641657431 has 2 divisors, whose sum is σ = 641657432. Its totient is φ = 641657430.

The previous prime is 641657413. The next prime is 641657453. The reversal of 641657431 is 134756146.

Together with previous prime (641657413) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 641657431 - 2¹¹ = 641655383 is a prime.

It is a super-2 number, since 2×641657431² = 823448517515039522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (641657491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320828715 + 320828716.

It is an arithmetic number, because the mean of its divisors is an integer number (320828716).

Almost surely, 2^641657431 is an apocalyptic number.

641657431 is a deficient number, since it is larger than the sum of its proper divisors (1).

641657431 is an equidigital number, since it uses as much as digits as its factorization.

641657431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 60480, while the sum is 37.

The square root of 641657431 is about 25330.9579566190. The cubic root of 641657431 is about 862.5171570066.

The spelling of 641657431 in words is "six hundred forty-one million, six hundred fifty-seven thousand, four hundred thirty-one".