640887199 has 4 divisors (see below), whose sum is σ = 678586464. Its totient is φ = 603187936.

The previous prime is 640887173. The next prime is 640887217. The reversal of 640887199 is 991788046.

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 640887199 - 2²³ = 632498591 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 (640887799) 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, 18849607 + ... + 18849640.

It is an arithmetic number, because the mean of its divisors is an integer number (169646616).

Almost surely, 2^640887199 is an apocalyptic number.

640887199 is a deficient number, since it is larger than the sum of its proper divisors (37699265).

640887199 is a wasteful number, since it uses less digits than its factorization.

640887199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37699264.

The product of its (nonzero) digits is 870912, while the sum is 52.

The square root of 640887199 is about 25315.7500185161. The cubic root of 640887199 is about 862.1719030443.

The spelling of 640887199 in words is "six hundred forty million, eight hundred eighty-seven thousand, one hundred ninety-nine".