81245985919 has 16 divisors (see below), whose sum is σ = 95238823680. Its totient is φ = 67857451200.

The previous prime is 81245985917. The next prime is 81245985941. The reversal of 81245985919 is 91958954218.

It is not a de Polignac number, because 81245985919 - 2¹ = 81245985917 is a prime.

It is a super-2 number, since 2×81245985919² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81245985911) 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, 195982 + ... + 448219.

It is an arithmetic number, because the mean of its divisors is an integer number (5952426480).

Almost surely, 2^81245985919 is an apocalyptic number.

81245985919 is a deficient number, since it is larger than the sum of its proper divisors (13992837761).

81245985919 is a wasteful number, since it uses less digits than its factorization.

81245985919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 644670.

The product of its digits is 9331200, while the sum is 61.

The spelling of 81245985919 in words is "eighty-one billion, two hundred forty-five million, nine hundred eighty-five thousand, nine hundred nineteen".