91345781 has 4 divisors (see below), whose sum is σ = 91377792. Its totient is φ = 91313772.

The previous prime is 91345759. The next prime is 91345801. The reversal of 91345781 is 18754319.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91345781 is a prime.

It is a super-2 number, since 2×91345781² = 16688103412999922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91345381) 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, 11255 + ... + 17588.

It is an arithmetic number, because the mean of its divisors is an integer number (22844448).

Almost surely, 2^91345781 is an apocalyptic number.

It is an amenable number.

91345781 is a deficient number, since it is larger than the sum of its proper divisors (32011).

91345781 is a wasteful number, since it uses less digits than its factorization.

91345781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32010.

The product of its digits is 30240, while the sum is 38.

The square root of 91345781 is about 9557.4986790478. The cubic root of 91345781 is about 450.3631324019.

The spelling of 91345781 in words is "ninety-one million, three hundred forty-five thousand, seven hundred eighty-one".