1665166387525 has 12 divisors (see below), whose sum is σ = 2108738371392. Its totient is φ = 1303789851440.

The previous prime is 1665166387517. The next prime is 1665166387579. The reversal of 1665166387525 is 5257836615661.

It is not a de Polignac number, because 1665166387525 - 2³ = 1665166387517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 708580267 + ... + 708582616.

It is an arithmetic number, because the mean of its divisors is an integer number (175728197616).

Almost surely, 2^{1665166387525} is an apocalyptic number.

It is an amenable number.

1665166387525 is a deficient number, since it is larger than the sum of its proper divisors (443571983867).

1665166387525 is a wasteful number, since it uses less digits than its factorization.

1665166387525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1417162940 (or 1417162935 counting only the distinct ones).

The product of its digits is 54432000, while the sum is 61.

The spelling of 1665166387525 in words is "one trillion, six hundred sixty-five billion, one hundred sixty-six million, three hundred eighty-seven thousand, five hundred twenty-five".