81439877566 has 8 divisors (see below), whose sum is σ = 127471112784. Its totient is φ = 38949506640.

The previous prime is 81439877549. The next prime is 81439877579. The reversal of 81439877566 is 66577893418.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 81439877498 and 81439877507.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 885216015 + ... + 885216106.

It is an arithmetic number, because the mean of its divisors is an integer number (15933889098).

Almost surely, 2^81439877566 is an apocalyptic number.

81439877566 is a deficient number, since it is larger than the sum of its proper divisors (46031235218).

81439877566 is a wasteful number, since it uses less digits than its factorization.

81439877566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1770432146.

The product of its digits is 60963840, while the sum is 64.

The spelling of 81439877566 in words is "eighty-one billion, four hundred thirty-nine million, eight hundred seventy-seven thousand, five hundred sixty-six".