161666025 has 24 divisors (see below), whose sum is σ = 273509280. Its totient is φ = 84215040.

The previous prime is 161666017. The next prime is 161666051. The reversal of 161666025 is 520666161.

It is not a de Polignac number, because 161666025 - 2³ = 161666017 is a prime.

It is a super-2 number, since 2×161666025² = 52271807278601250, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21840 + ... + 28289.

It is an arithmetic number, because the mean of its divisors is an integer number (11396220).

Almost surely, 2^161666025 is an apocalyptic number.

161666025 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161666025 is a deficient number, since it is larger than the sum of its proper divisors (111843255).

161666025 is a wasteful number, since it uses less digits than its factorization.

161666025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50185 (or 50180 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 161666025 is about 12714.7955154615. The cubic root of 161666025 is about 544.7613072533.

The spelling of 161666025 in words is "one hundred sixty-one million, six hundred sixty-six thousand, twenty-five".