81945188458 has 16 divisors (see below), whose sum is σ = 140536226880. Its totient is φ = 35104676256.

The previous prime is 81945188447. The next prime is 81945188477. The reversal of 81945188458 is 85488154918.

It is a super-2 number, since 2×81945188458² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81945188396 and 81945188405.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1189488 + ... + 1256491.

It is an arithmetic number, because the mean of its divisors is an integer number (8783514180).

Almost surely, 2^81945188458 is an apocalyptic number.

81945188458 is a deficient number, since it is larger than the sum of its proper divisors (58591038422).

81945188458 is a wasteful number, since it uses less digits than its factorization.

81945188458 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2448381.

The product of its digits is 14745600, while the sum is 61.

The spelling of 81945188458 in words is "eighty-one billion, nine hundred forty-five million, one hundred eighty-eight thousand, four hundred fifty-eight".