640779722 has 16 divisors (see below), whose sum is σ = 1072935072. Its totient is φ = 284489520.

The previous prime is 640779719. The next prime is 640779739. The reversal of 640779722 is 227977046.

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, 337733 + ... + 339624.

It is an arithmetic number, because the mean of its divisors is an integer number (67058442).

Almost surely, 2^640779722 is an apocalyptic number.

640779722 is a deficient number, since it is larger than the sum of its proper divisors (432155350).

640779722 is a wasteful number, since it uses less digits than its factorization.

640779722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 677413.

The product of its (nonzero) digits is 296352, while the sum is 44.

The square root of 640779722 is about 25313.6271995935. The cubic root of 640779722 is about 862.1237048433.

The spelling of 640779722 in words is "six hundred forty million, seven hundred seventy-nine thousand, seven hundred twenty-two".