2166509825 has 12 divisors (see below), whose sum is σ = 2720480640. Its totient is φ = 1711266960.

The previous prime is 2166509819. The next prime is 2166509831. The reversal of 2166509825 is 5289056612.

It is an interprime number because it is at equal distance from previous prime (2166509819) and next prime (2166509831).

It is a de Polignac number, because none of the positive numbers 2^k-2166509825 is a prime.

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, 546509 + ... + 550458.

It is an arithmetic number, because the mean of its divisors is an integer number (226706720).

Almost surely, 2^2166509825 is an apocalyptic number.

2166509825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

2166509825 is a deficient number, since it is larger than the sum of its proper divisors (553970815).

2166509825 is a wasteful number, since it uses less digits than its factorization.

2166509825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1097056 (or 1097051 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 44.

The square root of 2166509825 is about 46545.7820323174. The cubic root of 2166509825 is about 1293.9581220566.

The spelling of 2166509825 in words is "two billion, one hundred sixty-six million, five hundred nine thousand, eight hundred twenty-five".