641637999 has 24 divisors (see below), whose sum is σ = 976766960. Its totient is φ = 404756352.

The previous prime is 641637989. The next prime is 641638001. The reversal of 641637999 is 999736146.

It is not a de Polignac number, because 641637999 - 2⁹ = 641637487 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 (641637989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 185187 + ... + 188619.

Almost surely, 2^641637999 is an apocalyptic number.

641637999 is a deficient number, since it is larger than the sum of its proper divisors (335128961).

641637999 is a wasteful number, since it uses less digits than its factorization.

641637999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4551 (or 4548 counting only the distinct ones).

The product of its digits is 2204496, while the sum is 54.

The square root of 641637999 is about 25330.5743914346. The cubic root of 641637999 is about 862.5084500747.

The spelling of 641637999 in words is "six hundred forty-one million, six hundred thirty-seven thousand, nine hundred ninety-nine".