640964920639 has 8 divisors (see below), whose sum is σ = 644456933120. Its totient is φ = 637481194200.

The previous prime is 640964920613. The next prime is 640964920643. The reversal of 640964920639 is 936029469046.

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 640964920639 - 2¹¹ = 640964918591 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640964920679) 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, 1916349 + ... + 2225830.

It is an arithmetic number, because the mean of its divisors is an integer number (80557116640).

Almost surely, 2^640964920639 is an apocalyptic number.

640964920639 is a deficient number, since it is larger than the sum of its proper divisors (3492012481).

640964920639 is a wasteful number, since it uses less digits than its factorization.

640964920639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4143021.

The product of its (nonzero) digits is 15116544, while the sum is 58.

The spelling of 640964920639 in words is "six hundred forty billion, nine hundred sixty-four million, nine hundred twenty thousand, six hundred thirty-nine".