640293377 has 2 divisors, whose sum is σ = 640293378. Its totient is φ = 640293376.

The previous prime is 640293337. The next prime is 640293413. The reversal of 640293377 is 773392046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 640292416 + 961 = 25304^2 + 31^2 .

It is a cyclic number.

It is not a de Polignac number, because 640293377 - 2¹⁰ = 640292353 is a prime.

It is not a weakly prime, because it can be changed into another prime (640293317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320146688 + 320146689.

It is an arithmetic number, because the mean of its divisors is an integer number (320146689).

Almost surely, 2^640293377 is an apocalyptic number.

It is an amenable number.

640293377 is a deficient number, since it is larger than the sum of its proper divisors (1).

640293377 is an equidigital number, since it uses as much as digits as its factorization.

640293377 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 190512, while the sum is 41.

The square root of 640293377 is about 25304.0189890855. The cubic root of 640293377 is about 861.9055353943.

The spelling of 640293377 in words is "six hundred forty million, two hundred ninety-three thousand, three hundred seventy-seven".