81409859476 has 18 divisors (see below), whose sum is σ = 156596238890. Its totient is φ = 37004481360.

The previous prime is 81409859459. The next prime is 81409859483. The reversal of 81409859476 is 67495890418.

It can be written as a sum of positive squares in only one way, i.e., 71543410576 + 9866448900 = 267476^2 + 99330^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 84100611 + ... + 84101578.

Almost surely, 2^81409859476 is an apocalyptic number.

It is an amenable number.

81409859476 is a deficient number, since it is larger than the sum of its proper divisors (75186379414).

81409859476 is a wasteful number, since it uses less digits than its factorization.

81409859476 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168202215 (or 168202202 counting only the distinct ones).

The product of its (nonzero) digits is 17418240, while the sum is 61.

The spelling of 81409859476 in words is "eighty-one billion, four hundred nine million, eight hundred fifty-nine thousand, four hundred seventy-six".