641691031 has 2 divisors, whose sum is σ = 641691032. Its totient is φ = 641691030.

The previous prime is 641691023. The next prime is 641691079. The reversal of 641691031 is 130196146.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 641691031 - 2³ = 641691023 is a prime.

It is a super-2 number, since 2×641691031² = 823534758531685922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 641690984 and 641691002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (641691331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320845515 + 320845516.

It is an arithmetic number, because the mean of its divisors is an integer number (320845516).

Almost surely, 2^641691031 is an apocalyptic number.

641691031 is a deficient number, since it is larger than the sum of its proper divisors (1).

641691031 is an equidigital number, since it uses as much as digits as its factorization.

641691031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 641691031 is about 25331.6211680184. The cubic root of 641691031 is about 862.5322118054.

The spelling of 641691031 in words is "six hundred forty-one million, six hundred ninety-one thousand, thirty-one".