91781229413 has 4 divisors (see below), whose sum is σ = 91824099948. Its totient is φ = 91738358880.

The previous prime is 91781229367. The next prime is 91781229439. The reversal of 91781229413 is 31492218719.

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 90481843204 + 1299386209 = 300802^2 + 36047^2 .

It is a cyclic number.

It is not a de Polignac number, because 91781229413 - 2¹² = 91781225317 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91781229443) 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, 21432056 + ... + 21436337.

It is an arithmetic number, because the mean of its divisors is an integer number (22956024987).

Almost surely, 2^91781229413 is an apocalyptic number.

It is an amenable number.

91781229413 is a deficient number, since it is larger than the sum of its proper divisors (42870535).

91781229413 is a wasteful number, since it uses less digits than its factorization.

91781229413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42870534.

The product of its digits is 217728, while the sum is 47.

The spelling of 91781229413 in words is "ninety-one billion, seven hundred eighty-one million, two hundred twenty-nine thousand, four hundred thirteen".