91138866 has 64 divisors (see below), whose sum is σ = 227598336. Its totient is φ = 23688000.

The previous prime is 91138849. The next prime is 91138871. The reversal of 91138866 is 66883119.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 37591 + ... + 39941.

It is an arithmetic number, because the mean of its divisors is an integer number (3556224).

Almost surely, 2^91138866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91138866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113799168).

91138866 is an abundant number, since it is smaller than the sum of its proper divisors (136459470).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91138866 is a wasteful number, since it uses less digits than its factorization.

91138866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2447.

The product of its digits is 62208, while the sum is 42.

The square root of 91138866 is about 9546.6677956238. The cubic root of 91138866 is about 450.0228235338.

The spelling of 91138866 in words is "ninety-one million, one hundred thirty-eight thousand, eight hundred sixty-six".