641820731 has 2 divisors, whose sum is σ = 641820732. Its totient is φ = 641820730.

The previous prime is 641820719. The next prime is 641820733. The reversal of 641820731 is 137028146.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 641820731 - 2¹⁰ = 641819707 is a prime.

It is a super-2 number, since 2×641820731² = 823867701482748722, which contains 22 as substring.

Together with 641820733, 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 (641820733) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320910365 + 320910366.

It is an arithmetic number, because the mean of its divisors is an integer number (320910366).

Almost surely, 2^641820731 is an apocalyptic number.

641820731 is a deficient number, since it is larger than the sum of its proper divisors (1).

641820731 is an equidigital number, since it uses as much as digits as its factorization.

641820731 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 641820731 is about 25334.1810801139. The cubic root of 641820731 is about 862.5903201921.

Adding to 641820731 its reverse (137028146), we get a palindrome (778848877).

The spelling of 641820731 in words is "six hundred forty-one million, eight hundred twenty thousand, seven hundred thirty-one".