91005556 has 24 divisors (see below), whose sum is σ = 168920640. Its totient is φ = 42751872.

The previous prime is 91005511. The next prime is 91005557. The reversal of 91005556 is 65550019.

It is a happy number.

It is a super-2 number, since 2×91005556² = 16564022445738272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91005557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71655 + ... + 72913.

It is an arithmetic number, because the mean of its divisors is an integer number (7038360).

Almost surely, 2^91005556 is an apocalyptic number.

It is an amenable number.

91005556 is a deficient number, since it is larger than the sum of its proper divisors (77915084).

91005556 is a wasteful number, since it uses less digits than its factorization.

91005556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2343 (or 2341 counting only the distinct ones).

The product of its (nonzero) digits is 6750, while the sum is 31.

The square root of 91005556 is about 9539.6832232522. The cubic root of 91005556 is about 449.8032983935.

The spelling of 91005556 in words is "ninety-one million, five thousand, five hundred fifty-six".