91858780091 has 8 divisors (see below), whose sum is σ = 101337641664. Its totient is φ = 82724604480.

The previous prime is 91858780081. The next prime is 91858780133. The reversal of 91858780091 is 19008785819.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-91858780091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91858780061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 86170931 + ... + 86171996.

It is an arithmetic number, because the mean of its divisors is an integer number (12667205208).

Almost surely, 2^91858780091 is an apocalyptic number.

91858780091 is a deficient number, since it is larger than the sum of its proper divisors (9478861573).

91858780091 is a wasteful number, since it uses less digits than its factorization.

91858780091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172342981.

The product of its (nonzero) digits is 1451520, while the sum is 56.

The spelling of 91858780091 in words is "ninety-one billion, eight hundred fifty-eight million, seven hundred eighty thousand, ninety-one".