166561365 has 16 divisors (see below), whose sum is σ = 267172416. Its totient is φ = 88608000.

The previous prime is 166561327. The next prime is 166561411. The reversal of 166561365 is 563165661.

It is not a de Polignac number, because 166561365 - 2⁶ = 166561301 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7831 + ... + 19860.

It is an arithmetic number, because the mean of its divisors is an integer number (16698276).

Almost surely, 2^166561365 is an apocalyptic number.

166561365 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

166561365 is a deficient number, since it is larger than the sum of its proper divisors (100611051).

166561365 is a wasteful number, since it uses less digits than its factorization.

166561365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28100.

The product of its digits is 97200, while the sum is 39.

The square root of 166561365 is about 12905.8655269610. The cubic root of 166561365 is about 550.2052842509.

The spelling of 166561365 in words is "one hundred sixty-six million, five hundred sixty-one thousand, three hundred sixty-five".