640197629 has 2 divisors, whose sum is σ = 640197630. Its totient is φ = 640197628.

The previous prime is 640197601. The next prime is 640197641. The reversal of 640197629 is 926791046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 627252025 + 12945604 = 25045^2 + 3598^2 .

It is a cyclic number.

It is not a de Polignac number, because 640197629 - 2²⁸ = 371762173 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640197629.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640197689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320098814 + 320098815.

It is an arithmetic number, because the mean of its divisors is an integer number (320098815).

Almost surely, 2^640197629 is an apocalyptic number.

It is an amenable number.

640197629 is a deficient number, since it is larger than the sum of its proper divisors (1).

640197629 is an equidigital number, since it uses as much as digits as its factorization.

640197629 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 163296, while the sum is 44.

The square root of 640197629 is about 25302.1269659292. The cubic root of 640197629 is about 861.8625707950.

The spelling of 640197629 in words is "six hundred forty million, one hundred ninety-seven thousand, six hundred twenty-nine".