640635441 has 8 divisors (see below), whose sum is σ = 866929824. Its totient is φ = 420715680.

The previous prime is 640635421. The next prime is 640635467. The reversal of 640635441 is 144536046.

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

It is not a de Polignac number, because 640635441 - 2⁷ = 640635313 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640635421) 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, 1593420 + ... + 1593821.

It is an arithmetic number, because the mean of its divisors is an integer number (108366228).

Almost surely, 2^640635441 is an apocalyptic number.

It is an amenable number.

640635441 is a deficient number, since it is larger than the sum of its proper divisors (226294383).

640635441 is a wasteful number, since it uses less digits than its factorization.

640635441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3187311.

The product of its (nonzero) digits is 34560, while the sum is 33.

The square root of 640635441 is about 25310.7771709997. Note that the first 3 decimals coincide. The cubic root of 640635441 is about 862.0589933660.

The spelling of 640635441 in words is "six hundred forty million, six hundred thirty-five thousand, four hundred forty-one".