91155321 has 8 divisors (see below), whose sum is σ = 135044960. Its totient is φ = 60770196.

The previous prime is 91155307. The next prime is 91155329. The reversal of 91155321 is 12355119.

91155321 is a `hidden beast` number, since 91 + 1 + 553 + 21 = 666.

It is not a de Polignac number, because 91155321 - 2¹³ = 91147129 is a prime.

It is a super-2 number, since 2×91155321² = 16618585093226082, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 3376123 = 91155321 / (9 + 1 + 1 + 5 + 5 + 3 + 2 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91155329) 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, 1688035 + ... + 1688088.

It is an arithmetic number, because the mean of its divisors is an integer number (16880620).

Almost surely, 2^91155321 is an apocalyptic number.

It is an amenable number.

91155321 is a deficient number, since it is larger than the sum of its proper divisors (43889639).

91155321 is a wasteful number, since it uses less digits than its factorization.

91155321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3376132 (or 3376126 counting only the distinct ones).

The product of its digits is 1350, while the sum is 27.

The square root of 91155321 is about 9547.5295757594. The cubic root of 91155321 is about 450.0499055763.

The spelling of 91155321 in words is "ninety-one million, one hundred fifty-five thousand, three hundred twenty-one".