640900237 has 4 divisors (see below), whose sum is σ = 640958176. Its totient is φ = 640842300.

The previous prime is 640900213. The next prime is 640900241. The reversal of 640900237 is 732009046.

640900237 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 640900237 - 2⁷ = 640900109 is a prime.

It is a super-2 number, since 2×640900237² = 821506227573312338, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640900199 and 640900208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640900277) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6639 + ... + 36412.

It is an arithmetic number, because the mean of its divisors is an integer number (160239544).

Almost surely, 2^640900237 is an apocalyptic number.

It is an amenable number.

640900237 is a deficient number, since it is larger than the sum of its proper divisors (57939).

640900237 is a wasteful number, since it uses less digits than its factorization.

640900237 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57938.

The product of its (nonzero) digits is 9072, while the sum is 31.

The square root of 640900237 is about 25316.0075248843. The cubic root of 640900237 is about 862.1777495859.

The spelling of 640900237 in words is "six hundred forty million, nine hundred thousand, two hundred thirty-seven".