91555081 has 4 divisors (see below), whose sum is σ = 96940692. Its totient is φ = 86169472.

The previous prime is 91555069. The next prime is 91555097. The reversal of 91555081 is 18055519.

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

It can be written as a sum of positive squares in 2 ways, for example, as 46785600 + 44769481 = 6840^2 + 6691^2 .

It is a cyclic number.

It is not a de Polignac number, because 91555081 - 2⁹ = 91554569 is a prime.

It is a super-2 number, since 2×91555081² = 16764665713833122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91555181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2692780 + ... + 2692813.

It is an arithmetic number, because the mean of its divisors is an integer number (24235173).

Almost surely, 2^91555081 is an apocalyptic number.

It is an amenable number.

91555081 is a deficient number, since it is larger than the sum of its proper divisors (5385611).

91555081 is a wasteful number, since it uses less digits than its factorization.

91555081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5385610.

The product of its (nonzero) digits is 9000, while the sum is 34.

The square root of 91555081 is about 9568.4419316835. The cubic root of 91555081 is about 450.7068414048.

The spelling of 91555081 in words is "ninety-one million, five hundred fifty-five thousand, eighty-one".