640854373 has 4 divisors (see below), whose sum is σ = 641601280. Its totient is φ = 640107468.

The previous prime is 640854337. The next prime is 640854407. The reversal of 640854373 is 373458046.

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.

It is a cyclic number.

It is not a de Polignac number, because 640854373 - 2²⁵ = 607299941 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640854073) 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, 372165 + ... + 373882.

It is an arithmetic number, because the mean of its divisors is an integer number (160400320).

Almost surely, 2^640854373 is an apocalyptic number.

It is an amenable number.

640854373 is a deficient number, since it is larger than the sum of its proper divisors (746907).

640854373 is an equidigital number, since it uses as much as digits as its factorization.

640854373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 746906.

The product of its (nonzero) digits is 241920, while the sum is 40.

The square root of 640854373 is about 25315.1016786423. The cubic root of 640854373 is about 862.1571827533.

The spelling of 640854373 in words is "six hundred forty million, eight hundred fifty-four thousand, three hundred seventy-three".