858161891 has 2 divisors, whose sum is σ = 858161892. Its totient is φ = 858161890.

The previous prime is 858161869. The next prime is 858161951. The reversal of 858161891 is 198161858.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 858161891 - 2⁶ = 858161827 is a prime.

It is a super-3 number, since 3×858161891³ (a number of 28 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (858161851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 429080945 + 429080946.

It is an arithmetic number, because the mean of its divisors is an integer number (429080946).

Almost surely, 2^858161891 is an apocalyptic number.

858161891 is a deficient number, since it is larger than the sum of its proper divisors (1).

858161891 is an equidigital number, since it uses as much as digits as its factorization.

858161891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 138240, while the sum is 47.

The square root of 858161891 is about 29294.4003352177. The cubic root of 858161891 is about 950.2905449266.

The spelling of 858161891 in words is "eight hundred fifty-eight million, one hundred sixty-one thousand, eight hundred ninety-one".