1665564613557 has 32 divisors (see below), whose sum is σ = 2400606149760. Its totient is φ = 1021095694080.

The previous prime is 1665564613523. The next prime is 1665564613613. The reversal of 1665564613557 is 7553164655661.

It is a happy number.

It is not a de Polignac number, because 1665564613557 - 2⁷ = 1665564613429 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1665564613557.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665564613057) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 112981207 + ... + 112995947.

It is an arithmetic number, because the mean of its divisors is an integer number (75018942180).

Almost surely, 2^{1665564613557} is an apocalyptic number.

It is an amenable number.

1665564613557 is a deficient number, since it is larger than the sum of its proper divisors (735041536203).

1665564613557 is a wasteful number, since it uses less digits than its factorization.

1665564613557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25493.

The product of its digits is 68040000, while the sum is 60.

The spelling of 1665564613557 in words is "one trillion, six hundred sixty-five billion, five hundred sixty-four million, six hundred thirteen thousand, five hundred fifty-seven".