91881771 has 4 divisors (see below), whose sum is σ = 122509032. Its totient is φ = 61254512.

The previous prime is 91881749. The next prime is 91881781. The reversal of 91881771 is 17718819.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 91881771 - 2⁹ = 91881259 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91881721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15313626 + ... + 15313631.

It is an arithmetic number, because the mean of its divisors is an integer number (30627258).

Almost surely, 2^91881771 is an apocalyptic number.

91881771 is a deficient number, since it is larger than the sum of its proper divisors (30627261).

91881771 is a wasteful number, since it uses less digits than its factorization.

91881771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30627260.

The product of its digits is 28224, while the sum is 42.

The square root of 91881771 is about 9585.4979526366. The cubic root of 91881771 is about 451.2422809534.

The spelling of 91881771 in words is "ninety-one million, eight hundred eighty-one thousand, seven hundred seventy-one".