81558249190 has 64 divisors (see below), whose sum is σ = 173707426368. Its totient is φ = 27232153600.

The previous prime is 81558249187. The next prime is 81558249203. The reversal of 81558249190 is 9194285518.

It is a happy number.

It is a super-2 number, since 2×81558249190² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 455209 + ... + 608548.

It is an arithmetic number, because the mean of its divisors is an integer number (2714178537).

Almost surely, 2^81558249190 is an apocalyptic number.

81558249190 is an abundant number, since it is smaller than the sum of its proper divisors (92149177178).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81558249190 is a wasteful number, since it uses less digits than its factorization.

81558249190 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1063833.

The product of its (nonzero) digits is 1036800, while the sum is 52.

The spelling of 81558249190 in words is "eighty-one billion, five hundred fifty-eight million, two hundred forty-nine thousand, one hundred ninety".