81585964131 has 16 divisors (see below), whose sum is σ = 126024505344. Its totient is φ = 45981912384.

The previous prime is 81585964091. The next prime is 81585964133. The reversal of 81585964131 is 13146958518.

It is not a de Polignac number, because 81585964131 - 2⁷ = 81585964003 is a prime.

It is a super-2 number, since 2×81585964131² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81585964133) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26608371 + ... + 26611436.

It is an arithmetic number, because the mean of its divisors is an integer number (7876531584).

Almost surely, 2^81585964131 is an apocalyptic number.

81585964131 is a deficient number, since it is larger than the sum of its proper divisors (44438541213).

81585964131 is a wasteful number, since it uses less digits than its factorization.

81585964131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53219890.

The product of its digits is 1036800, while the sum is 51.

The spelling of 81585964131 in words is "eighty-one billion, five hundred eighty-five million, nine hundred sixty-four thousand, one hundred thirty-one".