91157538949 has 2 divisors, whose sum is σ = 91157538950. Its totient is φ = 91157538948.

The previous prime is 91157538937. The next prime is 91157539001. The reversal of 91157538949 is 94983575119.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78110188324 + 13047350625 = 279482^2 + 114225^2 .

It is an emirp because it is prime and its reverse (94983575119) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91157538949 - 2⁵ = 91157538917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91157538449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45578769474 + 45578769475.

It is an arithmetic number, because the mean of its divisors is an integer number (45578769475).

Almost surely, 2^91157538949 is an apocalyptic number.

It is an amenable number.

91157538949 is a deficient number, since it is larger than the sum of its proper divisors (1).

91157538949 is an equidigital number, since it uses as much as digits as its factorization.

91157538949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12247200, while the sum is 61.

The spelling of 91157538949 in words is "ninety-one billion, one hundred fifty-seven million, five hundred thirty-eight thousand, nine hundred forty-nine".