172261866 has 64 divisors (see below), whose sum is σ = 417715200. Its totient is φ = 46262016.

The previous prime is 172261861. The next prime is 172261883. The reversal of 172261866 is 668162271.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (172261861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 110146 + ... + 111698.

It is an arithmetic number, because the mean of its divisors is an integer number (6526800).

Almost surely, 2^172261866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 172261866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (208857600).

172261866 is an abundant number, since it is smaller than the sum of its proper divisors (245453334).

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

172261866 is a wasteful number, since it uses less digits than its factorization.

172261866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1723.

The product of its digits is 48384, while the sum is 39.

The square root of 172261866 is about 13124.8567992188. The cubic root of 172261866 is about 556.4118650934.

The spelling of 172261866 in words is "one hundred seventy-two million, two hundred sixty-one thousand, eight hundred sixty-six".