20171868 has 24 divisors (see below), whose sum is σ = 47335680. Its totient is φ = 6685680.

The previous prime is 20171861. The next prime is 20171873. The reversal of 20171868 is 86817102.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20171861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2548 + ... + 6843.

It is an arithmetic number, because the mean of its divisors is an integer number (1972320).

Almost surely, 2^20171868 is an apocalyptic number.

It is an amenable number.

20171868 is an abundant number, since it is smaller than the sum of its proper divisors (27163812).

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

20171868 is a wasteful number, since it uses less digits than its factorization.

20171868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9577 (or 9575 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 33.

The square root of 20171868 is about 4491.3102765229. The cubic root of 20171868 is about 272.2170808846.

The spelling of 20171868 in words is "twenty million, one hundred seventy-one thousand, eight hundred sixty-eight".