640889793 has 16 divisors (see below), whose sum is σ = 958688640. Its totient is φ = 423109872.

The previous prime is 640889761. The next prime is 640889803. The reversal of 640889793 is 397988046.

It is not a de Polignac number, because 640889793 - 2⁵ = 640889761 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640889713) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 112446 + ... + 118007.

It is an arithmetic number, because the mean of its divisors is an integer number (59918040).

Almost surely, 2^640889793 is an apocalyptic number.

It is an amenable number.

640889793 is a deficient number, since it is larger than the sum of its proper divisors (317798847).

640889793 is a wasteful number, since it uses less digits than its factorization.

640889793 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230565 (or 230559 counting only the distinct ones).

The product of its (nonzero) digits is 2612736, while the sum is 54.

The square root of 640889793 is about 25315.8012513924. The cubic root of 640889793 is about 862.1730662604.

The spelling of 640889793 in words is "six hundred forty million, eight hundred eighty-nine thousand, seven hundred ninety-three".