640622999 has 4 divisors (see below), whose sum is σ = 640676400. Its totient is φ = 640569600.

The previous prime is 640622993. The next prime is 640623001. The reversal of 640622999 is 999226046.

640622999 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640622999 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 (640622993) 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, 599 + ... + 35799.

It is an arithmetic number, because the mean of its divisors is an integer number (160169100).

Almost surely, 2^640622999 is an apocalyptic number.

640622999 is a deficient number, since it is larger than the sum of its proper divisors (53401).

640622999 is a wasteful number, since it uses less digits than its factorization.

640622999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53400.

The product of its (nonzero) digits is 419904, while the sum is 47.

The square root of 640622999 is about 25310.5313851764. The cubic root of 640622999 is about 862.0534125490.

The spelling of 640622999 in words is "six hundred forty million, six hundred twenty-two thousand, nine hundred ninety-nine".