91985866819 has 64 divisors (see below), whose sum is σ = 118293626880. Its totient is φ = 69464304000.

The previous prime is 91985866757. The next prime is 91985866823. The reversal of 91985866819 is 91866858919.

It is not a de Polignac number, because 91985866819 - 2²¹ = 91983769667 is a prime.

It is a super-2 number, since 2×91985866819² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (91985866859) 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 in 63 ways as a sum of consecutive naturals, for example, 161095804 + ... + 161096374.

It is an arithmetic number, because the mean of its divisors is an integer number (1848337920).

Almost surely, 2^91985866819 is an apocalyptic number.

91985866819 is a deficient number, since it is larger than the sum of its proper divisors (26307760061).

91985866819 is a wasteful number, since it uses less digits than its factorization.

91985866819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1112.

The product of its digits is 67184640, while the sum is 70.

The spelling of 91985866819 in words is "ninety-one billion, nine hundred eighty-five million, eight hundred sixty-six thousand, eight hundred nineteen".