1665165661556 has 24 divisors (see below), whose sum is σ = 3089054424456. Its totient is φ = 782692981760.

The previous prime is 1665165661547. The next prime is 1665165661567. The reversal of 1665165661556 is 6551665615661.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1357178400400 + 307987261156 = 1164980^2 + 554966^2 .

It is a super-2 number, since 2×1665165661556² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1665165661495 and 1665165661504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14228615 + ... + 14345166.

It is an arithmetic number, because the mean of its divisors is an integer number (128710601019).

Almost surely, 2^{1665165661556} is an apocalyptic number.

It is an amenable number.

1665165661556 is a deficient number, since it is larger than the sum of its proper divisors (1423888762900).

1665165661556 is a wasteful number, since it uses less digits than its factorization.

1665165661556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28574659 (or 28574657 counting only the distinct ones).

The product of its digits is 29160000, while the sum is 59.

The spelling of 1665165661556 in words is "one trillion, six hundred sixty-five billion, one hundred sixty-five million, six hundred sixty-one thousand, five hundred fifty-six".