91771939 has 4 divisors (see below), whose sum is σ = 104882224. Its totient is φ = 78661656.

The previous prime is 91771903. The next prime is 91771961. The reversal of 91771939 is 93917719.

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 91771939 - 2¹³ = 91763747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91771969) 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, 6555132 + ... + 6555145.

It is an arithmetic number, because the mean of its divisors is an integer number (26220556).

Almost surely, 2^91771939 is an apocalyptic number.

91771939 is a deficient number, since it is larger than the sum of its proper divisors (13110285).

91771939 is a wasteful number, since it uses less digits than its factorization.

91771939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13110284.

The product of its digits is 107163, while the sum is 46.

The square root of 91771939 is about 9579.7671683606. The cubic root of 91771939 is about 451.0624099354.

The spelling of 91771939 in words is "ninety-one million, seven hundred seventy-one thousand, nine hundred thirty-nine".