640474901 has 6 divisors (see below), whose sum is σ = 703993206. Its totient is φ = 582249800.

The previous prime is 640474897. The next prime is 640474957. The reversal of 640474901 is 109474046.

It can be written as a sum of positive squares in only one way, i.e., 467683876 + 172791025 = 21626^2 + 13145^2 .

It is not a de Polignac number, because 640474901 - 2² = 640474897 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 (640474001) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2646470 + ... + 2646711.

It is an arithmetic number, because the mean of its divisors is an integer number (117332201).

Almost surely, 2^640474901 is an apocalyptic number.

It is an amenable number.

640474901 is a deficient number, since it is larger than the sum of its proper divisors (63518305).

640474901 is a wasteful number, since it uses less digits than its factorization.

640474901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5293203 (or 5293192 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 35.

The square root of 640474901 is about 25307.6055959468. The cubic root of 640474901 is about 861.9869781428.

The spelling of 640474901 in words is "six hundred forty million, four hundred seventy-four thousand, nine hundred one".