640066711 has 4 divisors (see below), whose sum is σ = 677717712. Its totient is φ = 602415712.

The previous prime is 640066709. The next prime is 640066723. The reversal of 640066711 is 117660046.

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 640066711 - 2¹ = 640066709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640066741) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18825475 + ... + 18825508.

It is an arithmetic number, because the mean of its divisors is an integer number (169429428).

Almost surely, 2^640066711 is an apocalyptic number.

640066711 is a deficient number, since it is larger than the sum of its proper divisors (37651001).

640066711 is a wasteful number, since it uses less digits than its factorization.

640066711 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37651000.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 640066711 is about 25299.5397388964. The cubic root of 640066711 is about 861.8038175751.

The spelling of 640066711 in words is "six hundred forty million, sixty-six thousand, seven hundred eleven".