2640487673561 has 4 divisors (see below), whose sum is σ = 2641021002624. Its totient is φ = 2639954344500.

The previous prime is 2640487673513. The next prime is 2640487673567. The reversal of 2640487673561 is 1653767840462.

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 a de Polignac number, because none of the positive numbers 2^k-2640487673561 is a prime.

It is a super-4 number, since 4×2640487673561⁴ (a number of 51 digits) contains 4444 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2640487673561.

It is not an unprimeable number, because it can be changed into a prime (2640487673567) 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, 266657105 + ... + 266667006.

It is an arithmetic number, because the mean of its divisors is an integer number (660255250656).

Almost surely, 2^{2640487673561} is an apocalyptic number.

It is an amenable number.

2640487673561 is a deficient number, since it is larger than the sum of its proper divisors (533329063).

2640487673561 is an equidigital number, since it uses as much as digits as its factorization.

2640487673561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 533329062.

The product of its (nonzero) digits is 40642560, while the sum is 59.

The spelling of 2640487673561 in words is "two trillion, six hundred forty billion, four hundred eighty-seven million, six hundred seventy-three thousand, five hundred sixty-one".