81861459736 has 16 divisors (see below), whose sum is σ = 175417413840. Its totient is φ = 35083482720.

The previous prime is 81861459727. The next prime is 81861459809. The reversal of 81861459736 is 63795416818.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 730905835 + ... + 730905946.

It is an arithmetic number, because the mean of its divisors is an integer number (10963588365).

Almost surely, 2^81861459736 is an apocalyptic number.

It is an amenable number.

81861459736 is an abundant number, since it is smaller than the sum of its proper divisors (93555954104).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81861459736 is a wasteful number, since it uses less digits than its factorization.

81861459736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1461811794 (or 1461811790 counting only the distinct ones).

The product of its digits is 8709120, while the sum is 58.

The spelling of 81861459736 in words is "eighty-one billion, eight hundred sixty-one million, four hundred fifty-nine thousand, seven hundred thirty-six".