640989801 has 16 divisors (see below), whose sum is σ = 950515200. Its totient is φ = 426921264.

The previous prime is 640989799. The next prime is 640989823. The reversal of 640989801 is 108989046.

640989801 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 640989801 - 2¹ = 640989799 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (640989101) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19240 + ... + 40646.

It is an arithmetic number, because the mean of its divisors is an integer number (59407200).

Almost surely, 2^640989801 is an apocalyptic number.

It is an amenable number.

640989801 is a deficient number, since it is larger than the sum of its proper divisors (309525399).

640989801 is a wasteful number, since it uses less digits than its factorization.

640989801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22525 (or 22519 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The square root of 640989801 is about 25317.7763834030. The cubic root of 640989801 is about 862.2179100179.

The spelling of 640989801 in words is "six hundred forty million, nine hundred eighty-nine thousand, eight hundred one".