91861859 has 4 divisors (see below), whose sum is σ = 93155760. Its totient is φ = 90567960.

The previous prime is 91861843. The next prime is 91861873. The reversal of 91861859 is 95816819.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 91861859 - 2⁴ = 91861843 is a prime.

It is a super-2 number, since 2×91861859² = 16877202277871762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91864859) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 646844 + ... + 646985.

It is an arithmetic number, because the mean of its divisors is an integer number (23288940).

Almost surely, 2^91861859 is an apocalyptic number.

91861859 is a deficient number, since it is larger than the sum of its proper divisors (1293901).

91861859 is a wasteful number, since it uses less digits than its factorization.

91861859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1293900.

The product of its digits is 155520, while the sum is 47.

The square root of 91861859 is about 9584.4592440054. The cubic root of 91861859 is about 451.2096818667.

The spelling of 91861859 in words is "ninety-one million, eight hundred sixty-one thousand, eight hundred fifty-nine".