640989474 has 16 divisors (see below), whose sum is σ = 1285554240. Its totient is φ = 213067280.

The previous prime is 640989467. The next prime is 640989509. The reversal of 640989474 is 474989046.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 146637 + ... + 150944.

It is an arithmetic number, because the mean of its divisors is an integer number (80347140).

Almost surely, 2^640989474 is an apocalyptic number.

640989474 is an abundant number, since it is smaller than the sum of its proper divisors (644564766).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640989474 is a wasteful number, since it uses less digits than its factorization.

640989474 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 297945.

The product of its (nonzero) digits is 1741824, while the sum is 51.

The square root of 640989474 is about 25317.7699254891. The cubic root of 640989474 is about 862.2177633981.

The spelling of 640989474 in words is "six hundred forty million, nine hundred eighty-nine thousand, four hundred seventy-four".