640090173 has 4 divisors (see below), whose sum is σ = 853453568. Its totient is φ = 426726780.

The previous prime is 640090159. The next prime is 640090211. The reversal of 640090173 is 371090046.

It is a happy number.

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 not a de Polignac number, because 640090173 - 2¹⁴ = 640073789 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 640090173.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640090673) 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, 106681693 + ... + 106681698.

It is an arithmetic number, because the mean of its divisors is an integer number (213363392).

Almost surely, 2^640090173 is an apocalyptic number.

It is an amenable number.

640090173 is a deficient number, since it is larger than the sum of its proper divisors (213363395).

640090173 is a wasteful number, since it uses less digits than its factorization.

640090173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213363394.

The product of its (nonzero) digits is 4536, while the sum is 30.

The square root of 640090173 is about 25300.0034189721. The cubic root of 640090173 is about 861.8143474119.

The spelling of 640090173 in words is "six hundred forty million, ninety thousand, one hundred seventy-three".