3640563661 has 4 divisors (see below), whose sum is σ = 4160644192. Its totient is φ = 3120483132.

The previous prime is 3640563659. The next prime is 3640563673. The reversal of 3640563661 is 1663650463.

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 3640563661 - 2¹ = 3640563659 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 (3640563361) 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, 260040255 + ... + 260040268.

It is an arithmetic number, because the mean of its divisors is an integer number (1040161048).

Almost surely, 2^3640563661 is an apocalyptic number.

It is an amenable number.

3640563661 is a deficient number, since it is larger than the sum of its proper divisors (520080531).

3640563661 is an equidigital number, since it uses as much as digits as its factorization.

3640563661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520080530.

The product of its (nonzero) digits is 233280, while the sum is 40.

The square root of 3640563661 is about 60337.0836302187. The cubic root of 3640563661 is about 1538.3537336778.

The spelling of 3640563661 in words is "three billion, six hundred forty million, five hundred sixty-three thousand, six hundred sixty-one".