643807631 has 8 divisors (see below), whose sum is σ = 649004928. Its totient is φ = 638631000.

The previous prime is 643807621. The next prime is 643807649. The reversal of 643807631 is 136708346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 643807631 - 2¹⁰ = 643806607 is a prime.

It is a super-2 number, since 2×643807631² = 828976531467664322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643807621) 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 7 ways as a sum of consecutive naturals, for example, 60716 + ... + 70526.

It is an arithmetic number, because the mean of its divisors is an integer number (81125616).

Almost surely, 2^643807631 is an apocalyptic number.

643807631 is a deficient number, since it is larger than the sum of its proper divisors (5197297).

643807631 is a wasteful number, since it uses less digits than its factorization.

643807631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10333.

The product of its (nonzero) digits is 72576, while the sum is 38.

The square root of 643807631 is about 25373.3645975460. The cubic root of 643807631 is about 863.4795171763.

The spelling of 643807631 in words is "six hundred forty-three million, eight hundred seven thousand, six hundred thirty-one".