640361677 has 2 divisors, whose sum is σ = 640361678. Its totient is φ = 640361676.

The previous prime is 640361669. The next prime is 640361681. The reversal of 640361677 is 776163046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 638370756 + 1990921 = 25266^2 + 1411^2 .

It is a cyclic number.

It is not a de Polignac number, because 640361677 - 2³ = 640361669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640361647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320180838 + 320180839.

It is an arithmetic number, because the mean of its divisors is an integer number (320180839).

Almost surely, 2^640361677 is an apocalyptic number.

It is an amenable number.

640361677 is a deficient number, since it is larger than the sum of its proper divisors (1).

640361677 is an equidigital number, since it uses as much as digits as its factorization.

640361677 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 127008, while the sum is 40.

The square root of 640361677 is about 25305.3685410823. The cubic root of 640361677 is about 861.9361807501.

The spelling of 640361677 in words is "six hundred forty million, three hundred sixty-one thousand, six hundred seventy-seven".