640013601 has 4 divisors (see below), whose sum is σ = 853351472. Its totient is φ = 426675732.

The previous prime is 640013597. The next prime is 640013611. The reversal of 640013601 is 106310046.

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 640013601 - 2² = 640013597 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640013611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106668931 + ... + 106668936.

It is an arithmetic number, because the mean of its divisors is an integer number (213337868).

Almost surely, 2^640013601 is an apocalyptic number.

It is an amenable number.

640013601 is a deficient number, since it is larger than the sum of its proper divisors (213337871).

640013601 is a wasteful number, since it uses less digits than its factorization.

640013601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213337870.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 640013601 is about 25298.4900932842. The cubic root of 640013601 is about 861.7799806500.

Adding to 640013601 its reverse (106310046), we get a palindrome (746323647).

The spelling of 640013601 in words is "six hundred forty million, thirteen thousand, six hundred one".