640719494 has 8 divisors (see below), whose sum is σ = 1017613368. Its totient is φ = 301515040.

The previous prime is 640719473. The next prime is 640719503. The reversal of 640719494 is 494917046.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9422312 + ... + 9422379.

It is an arithmetic number, because the mean of its divisors is an integer number (127201671).

Almost surely, 2^640719494 is an apocalyptic number.

640719494 is a deficient number, since it is larger than the sum of its proper divisors (376893874).

640719494 is a wasteful number, since it uses less digits than its factorization.

640719494 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18844710.

The product of its (nonzero) digits is 217728, while the sum is 44.

The square root of 640719494 is about 25312.4375357254. The cubic root of 640719494 is about 862.0966931618.

The spelling of 640719494 in words is "six hundred forty million, seven hundred nineteen thousand, four hundred ninety-four".