81373337818 has 16 divisors (see below), whose sum is σ = 123397275456. Its totient is φ = 40241888640.

The previous prime is 81373337783. The next prime is 81373337819. The reversal of 81373337818 is 81873337318.

It is a super-2 number, since 2×81373337818² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81373337819) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 76471 + ... + 410602.

It is an arithmetic number, because the mean of its divisors is an integer number (7712329716).

Almost surely, 2^81373337818 is an apocalyptic number.

81373337818 is a deficient number, since it is larger than the sum of its proper divisors (42023937638).

81373337818 is a wasteful number, since it uses less digits than its factorization.

81373337818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 487989.

The product of its digits is 2032128, while the sum is 52.

The spelling of 81373337818 in words is "eighty-one billion, three hundred seventy-three million, three hundred thirty-seven thousand, eight hundred eighteen".