2640637645 has 8 divisors (see below), whose sum is σ = 3254407704. Its totient is φ = 2055415104.

The previous prime is 2640637639. The next prime is 2640637661. The reversal of 2640637645 is 5467360462.

It can be written as a sum of positive squares in 4 ways, for example, as 374306409 + 2266331236 = 19347^2 + 47606^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2640637645 - 2²¹ = 2638540493 is a prime.

It is a super-3 number, since 3×2640637645³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7136674 + ... + 7137043.

It is an arithmetic number, because the mean of its divisors is an integer number (406800963).

Almost surely, 2^2640637645 is an apocalyptic number.

It is an amenable number.

2640637645 is a deficient number, since it is larger than the sum of its proper divisors (613770059).

2640637645 is a wasteful number, since it uses less digits than its factorization.

2640637645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14273759.

The product of its (nonzero) digits is 725760, while the sum is 43.

The square root of 2640637645 is about 51387.1350145151. The cubic root of 2640637645 is about 1382.1959096918.

The spelling of 2640637645 in words is "two billion, six hundred forty million, six hundred thirty-seven thousand, six hundred forty-five".