640704611 has 4 divisors (see below), whose sum is σ = 654336672. Its totient is φ = 627072552.

The previous prime is 640704593. The next prime is 640704613. The reversal of 640704611 is 116407046.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 640704611 - 2¹⁰ = 640703587 is a prime.

It is a super-2 number, since 2×640704611² = 821004797113322642, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640704613) 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 3 ways as a sum of consecutive naturals, for example, 6815960 + ... + 6816053.

It is an arithmetic number, because the mean of its divisors is an integer number (163584168).

Almost surely, 2^640704611 is an apocalyptic number.

640704611 is a deficient number, since it is larger than the sum of its proper divisors (13632061).

640704611 is a wasteful number, since it uses less digits than its factorization.

640704611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13632060.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 640704611 is about 25312.1435481075. The cubic root of 640704611 is about 862.0900180179.

The spelling of 640704611 in words is "six hundred forty million, seven hundred four thousand, six hundred eleven".