81417618919 has 32 divisors (see below), whose sum is σ = 103483942016. Its totient is φ = 62330549760.

The previous prime is 81417618911. The next prime is 81417618943. The reversal of 81417618919 is 91981671418.

It is a cyclic number.

It is not a de Polignac number, because 81417618919 - 2³ = 81417618911 is a prime.

It is a super-2 number, since 2×81417618919² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81417618919.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81417618911) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 542629 + ... + 676225.

It is an arithmetic number, because the mean of its divisors is an integer number (3233873188).

Almost surely, 2^81417618919 is an apocalyptic number.

81417618919 is a deficient number, since it is larger than the sum of its proper divisors (22066323097).

81417618919 is a wasteful number, since it uses less digits than its factorization.

81417618919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133835.

The product of its digits is 870912, while the sum is 55.

It can be divided in two parts, 81417 and 618919, that added together give a triangular number (700336 = T₁₁₈₃).

The spelling of 81417618919 in words is "eighty-one billion, four hundred seventeen million, six hundred eighteen thousand, nine hundred nineteen".