640375693 has 2 divisors, whose sum is σ = 640375694. Its totient is φ = 640375692.

The previous prime is 640375691. The next prime is 640375699. The reversal of 640375693 is 396573046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 638421289 + 1954404 = 25267^2 + 1398^2 .

It is a cyclic number.

It is not a de Polignac number, because 640375693 - 2¹ = 640375691 is a prime.

Together with 640375691, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640375691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320187846 + 320187847.

It is an arithmetic number, because the mean of its divisors is an integer number (320187847).

Almost surely, 2^640375693 is an apocalyptic number.

It is an amenable number.

640375693 is a deficient number, since it is larger than the sum of its proper divisors (1).

640375693 is an equidigital number, since it uses as much as digits as its factorization.

640375693 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 408240, while the sum is 43.

The square root of 640375693 is about 25305.6454768496. The cubic root of 640375693 is about 861.9424692845.

The spelling of 640375693 in words is "six hundred forty million, three hundred seventy-five thousand, six hundred ninety-three".