91149831781 has 8 divisors (see below), whose sum is σ = 94267537920. Its totient is φ = 88081223568.

The previous prime is 91149831767. The next prime is 91149831793. The reversal of 91149831781 is 18713894119.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 91149831781 - 2⁷ = 91149831653 is a prime.

It is a super-2 number, since 2×91149831781² (a number of 23 digits) 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 (91149831701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12270706 + ... + 12278131.

It is an arithmetic number, because the mean of its divisors is an integer number (11783442240).

Almost surely, 2^91149831781 is an apocalyptic number.

It is an amenable number.

91149831781 is a deficient number, since it is larger than the sum of its proper divisors (3117706139).

91149831781 is a wasteful number, since it uses less digits than its factorization.

91149831781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24548963.

The product of its digits is 435456, while the sum is 52.

The spelling of 91149831781 in words is "ninety-one billion, one hundred forty-nine million, eight hundred thirty-one thousand, seven hundred eighty-one".