166720565 has 16 divisors (see below), whose sum is σ = 225780480. Its totient is φ = 117069120.

The previous prime is 166720531. The next prime is 166720577. The reversal of 166720565 is 565027661.

It is not a de Polignac number, because 166720565 - 2¹⁸ = 166458421 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, 50669 + ... + 53858.

It is an arithmetic number, because the mean of its divisors is an integer number (14111280).

Almost surely, 2^166720565 is an apocalyptic number.

It is an amenable number.

166720565 is a deficient number, since it is larger than the sum of its proper divisors (59059915).

166720565 is a wasteful number, since it uses less digits than its factorization.

166720565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104572.

The product of its (nonzero) digits is 75600, while the sum is 38.

The square root of 166720565 is about 12912.0317920922. The cubic root of 166720565 is about 550.3805245473.

The spelling of 166720565 in words is "one hundred sixty-six million, seven hundred twenty thousand, five hundred sixty-five".