81818931963 has 32 divisors (see below), whose sum is σ = 117032439040. Its totient is φ = 50692055040.

The previous prime is 81818931959. The next prime is 81818932003. The reversal of 81818931963 is 36913981818.

It is not a de Polignac number, because 81818931963 - 2² = 81818931959 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81818935963) 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, 875931 + ... + 964827.

It is an arithmetic number, because the mean of its divisors is an integer number (3657263720).

Almost surely, 2^81818931963 is an apocalyptic number.

81818931963 is a deficient number, since it is larger than the sum of its proper divisors (35213507077).

81818931963 is a wasteful number, since it uses less digits than its factorization.

81818931963 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89227.

The product of its digits is 2239488, while the sum is 57.

It can be divided in two parts, 818 and 18931963, that added together give a triangular number (18932781 = T₆₁₅₃).

The spelling of 81818931963 in words is "eighty-one billion, eight hundred eighteen million, nine hundred thirty-one thousand, nine hundred sixty-three".