640887711 has 4 divisors (see below), whose sum is σ = 854516952. Its totient is φ = 427258472.

The previous prime is 640887679. The next prime is 640887719. The reversal of 640887711 is 117788046.

It is a happy number.

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 640887711 - 2⁵ = 640887679 is a prime.

It is a super-2 number, since 2×640887711² = 821474116221639042, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640887719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106814616 + ... + 106814621.

It is an arithmetic number, because the mean of its divisors is an integer number (213629238).

Almost surely, 2^640887711 is an apocalyptic number.

640887711 is a deficient number, since it is larger than the sum of its proper divisors (213629241).

640887711 is a wasteful number, since it uses less digits than its factorization.

640887711 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213629240.

The product of its (nonzero) digits is 75264, while the sum is 42.

The square root of 640887711 is about 25315.7601307960. The cubic root of 640887711 is about 862.1721326385.

The spelling of 640887711 in words is "six hundred forty million, eight hundred eighty-seven thousand, seven hundred eleven".