640958479 has 8 divisors (see below), whose sum is σ = 732926880. Its totient is φ = 549090816.

The previous prime is 640958431. The next prime is 640958489. The reversal of 640958479 is 974859046.

It is a happy number.

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 640958479 - 2¹⁹ = 640434191 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640958489) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11014 + ... + 37459.

It is an arithmetic number, because the mean of its divisors is an integer number (91615860).

Almost surely, 2^640958479 is an apocalyptic number.

640958479 is a deficient number, since it is larger than the sum of its proper divisors (91968401).

640958479 is a wasteful number, since it uses less digits than its factorization.

640958479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50369.

The product of its (nonzero) digits is 2177280, while the sum is 52.

The square root of 640958479 is about 25317.1577986155. The cubic root of 640958479 is about 862.2038656815.

The spelling of 640958479 in words is "six hundred forty million, nine hundred fifty-eight thousand, four hundred seventy-nine".