640235601 has 12 divisors (see below), whose sum is σ = 942234228. Its totient is φ = 418770144.

The previous prime is 640235597. The next prime is 640235627. The reversal of 640235601 is 106532046.

It can be written as a sum of positive squares in 2 ways, for example, as 381186576 + 259049025 = 19524^2 + 16095^2 .

It is not a de Polignac number, because 640235601 - 2² = 640235597 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (640235641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 670630 + ... + 671583.

It is an arithmetic number, because the mean of its divisors is an integer number (78519519).

Almost surely, 2^640235601 is an apocalyptic number.

It is an amenable number.

640235601 is a deficient number, since it is larger than the sum of its proper divisors (301998627).

640235601 is a wasteful number, since it uses less digits than its factorization.

640235601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1342272 (or 1342269 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 640235601 is about 25302.8773265018. The cubic root of 640235601 is about 861.8796103242.

Adding to 640235601 its reverse (106532046), we get a palindrome (746767647).

The spelling of 640235601 in words is "six hundred forty million, two hundred thirty-five thousand, six hundred one".