643508401 has 8 divisors (see below), whose sum is σ = 656773920. Its totient is φ = 630350688.

The previous prime is 643508387. The next prime is 643508417. The reversal of 643508401 is 104805346.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643508401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643508431) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14836 + ... + 38821.

It is an arithmetic number, because the mean of its divisors is an integer number (82096740).

Almost surely, 2^643508401 is an apocalyptic number.

It is an amenable number.

643508401 is a deficient number, since it is larger than the sum of its proper divisors (13265519).

643508401 is a wasteful number, since it uses less digits than its factorization.

643508401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53903.

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 643508401 is about 25367.4673745725. The cubic root of 643508401 is about 863.3457199550.

The spelling of 643508401 in words is "six hundred forty-three million, five hundred eight thousand, four hundred one".