91047631081 has 9 divisors (see below), whose sum is σ = 100080796669. Its totient is φ = 82767556300.

The previous prime is 91047631057. The next prime is 91047631117. The reversal of 91047631081 is 18013674019.

The square root of 91047631081 is 301741.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 91047631081 - 2¹¹ = 91047629033 is a prime.

It is a super-2 number, since 2×91047631081² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91047631481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3305436 + ... + 3332866.

Almost surely, 2^91047631081 is an apocalyptic number.

91047631081 is the 301741-st square number.

91047631081 is the 150871-st centered octagonal number.

It is an amenable number.

91047631081 is a deficient number, since it is larger than the sum of its proper divisors (9033165588).

91047631081 is an frugal number, since it uses more digits than its factorization.

91047631081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54884 (or 27442 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 40.

The spelling of 91047631081 in words is "ninety-one billion, forty-seven million, six hundred thirty-one thousand, eighty-one".