81543692878 has 24 divisors (see below), whose sum is σ = 126329326200. Its totient is φ = 39473553600.

The previous prime is 81543692861. The next prime is 81543692981. The reversal of 81543692878 is 87829634518.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 347848 + ... + 532996.

It is an arithmetic number, because the mean of its divisors is an integer number (5263721925).

Almost surely, 2^81543692878 is an apocalyptic number.

81543692878 is a deficient number, since it is larger than the sum of its proper divisors (44785633322).

81543692878 is a wasteful number, since it uses less digits than its factorization.

81543692878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185364 (or 185323 counting only the distinct ones).

The product of its digits is 23224320, while the sum is 61.

The spelling of 81543692878 in words is "eighty-one billion, five hundred forty-three million, six hundred ninety-two thousand, eight hundred seventy-eight".