168261891 has 16 divisors (see below), whose sum is σ = 269894400. Its totient is φ = 91088928.

The previous prime is 168261889. The next prime is 168261911. The reversal of 168261891 is 198162861.

It is not a de Polignac number, because 168261891 - 2¹ = 168261889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (168261091) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 210456 + ... + 211253.

It is an arithmetic number, because the mean of its divisors is an integer number (16868400).

Almost surely, 2^168261891 is an apocalyptic number.

168261891 is a deficient number, since it is larger than the sum of its proper divisors (101632509).

168261891 is a wasteful number, since it uses less digits than its factorization.

168261891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421738.

The product of its digits is 41472, while the sum is 42.

The square root of 168261891 is about 12971.5801273399. The cubic root of 168261891 is about 552.0714076126.

The spelling of 168261891 in words is "one hundred sixty-eight million, two hundred sixty-one thousand, eight hundred ninety-one".