91138887 has 48 divisors (see below), whose sum is σ = 163088640. Its totient is φ = 47851776.

The previous prime is 91138871. The next prime is 91138913. The reversal of 91138887 is 78883119.

It is not a de Polignac number, because 91138887 - 2⁴ = 91138871 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91138847) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 45064 + ... + 47042.

It is an arithmetic number, because the mean of its divisors is an integer number (3397680).

Almost surely, 2^91138887 is an apocalyptic number.

91138887 is a deficient number, since it is larger than the sum of its proper divisors (71949753).

91138887 is a wasteful number, since it uses less digits than its factorization.

91138887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2052 (or 2049 counting only the distinct ones).

The product of its digits is 96768, while the sum is 45.

The square root of 91138887 is about 9546.6688954839. The cubic root of 91138887 is about 450.0228580981.

The spelling of 91138887 in words is "ninety-one million, one hundred thirty-eight thousand, eight hundred eighty-seven".