640765677 has 8 divisors (see below), whose sum is σ = 854701920. Its totient is φ = 427003280.

The previous prime is 640765669. The next prime is 640765681. The reversal of 640765677 is 776567046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640765677 - 2³ = 640765669 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640765637) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34602 + ... + 49787.

It is an arithmetic number, because the mean of its divisors is an integer number (106837740).

Almost surely, 2^640765677 is an apocalyptic number.

It is an amenable number.

640765677 is a deficient number, since it is larger than the sum of its proper divisors (213936243).

640765677 is a wasteful number, since it uses less digits than its factorization.

640765677 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86923.

The product of its (nonzero) digits is 1481760, while the sum is 48.

The square root of 640765677 is about 25313.3497783284. The cubic root of 640765677 is about 862.1174059466.

The spelling of 640765677 in words is "six hundred forty million, seven hundred sixty-five thousand, six hundred seventy-seven".