2165250025566 has 12 divisors (see below), whose sum is σ = 4691375055432. Its totient is φ = 721750008516.

The previous prime is 2165250025517. The next prime is 2165250025567. The reversal of 2165250025566 is 6655200525612.

2165250025566 is a `hidden beast` number, since 2 + 1 + 65 + 2 + 5 + 0 + 0 + 25 + 566 = 666.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2165250025567) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 60145834026 + ... + 60145834061.

It is an arithmetic number, because the mean of its divisors is an integer number (390947921286).

Almost surely, 2^{2165250025566} is an apocalyptic number.

2165250025566 is an abundant number, since it is smaller than the sum of its proper divisors (2526125029866).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2165250025566 is a wasteful number, since it uses less digits than its factorization.

2165250025566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120291668095 (or 120291668092 counting only the distinct ones).

The product of its (nonzero) digits is 1080000, while the sum is 45.

The spelling of 2165250025566 in words is "two trillion, one hundred sixty-five billion, two hundred fifty million, twenty-five thousand, five hundred sixty-six".