2640545565641 has 4 divisors (see below), whose sum is σ = 2640549745284. Its totient is φ = 2640541386000.

The previous prime is 2640545565571. The next prime is 2640545565659. The reversal of 2640545565641 is 1465655450462.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1302599929225 + 1337945636416 = 1141315^2 + 1156696^2 .

It is a cyclic number.

It is not a de Polignac number, because 2640545565641 - 2²² = 2640541371337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2640545565041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 926210 + ... + 2477691.

It is an arithmetic number, because the mean of its divisors is an integer number (660137436321).

Almost surely, 2^{2640545565641} is an apocalyptic number.

It is an amenable number.

2640545565641 is a deficient number, since it is larger than the sum of its proper divisors (4179643).

2640545565641 is an equidigital number, since it uses as much as digits as its factorization.

2640545565641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4179642.

The product of its (nonzero) digits is 17280000, while the sum is 53.

The spelling of 2640545565641 in words is "two trillion, six hundred forty billion, five hundred forty-five million, five hundred sixty-five thousand, six hundred forty-one".