91388761 has 4 divisors (see below), whose sum is σ = 92227300. Its totient is φ = 90550224.

The previous prime is 91388743. The next prime is 91388767. The reversal of 91388761 is 16788319.

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

It can be written as a sum of positive squares in 2 ways, for example, as 46498761 + 44890000 = 6819^2 + 6700^2 .

It is not a de Polignac number, because 91388761 - 2¹⁵ = 91355993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91388767) 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, 419106 + ... + 419323.

It is an arithmetic number, because the mean of its divisors is an integer number (23056825).

Almost surely, 2^91388761 is an apocalyptic number.

It is an amenable number.

91388761 is a deficient number, since it is larger than the sum of its proper divisors (838539).

91388761 is a wasteful number, since it uses less digits than its factorization.

91388761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 838538.

The product of its digits is 72576, while the sum is 43.

The square root of 91388761 is about 9559.7469108758. The cubic root of 91388761 is about 450.4337562524.

The spelling of 91388761 in words is "ninety-one million, three hundred eighty-eight thousand, seven hundred sixty-one".