81151419856 has 40 divisors (see below), whose sum is σ = 169866671240. Its totient is φ = 37334808576.

The previous prime is 81151419709. The next prime is 81151419863. The reversal of 81151419856 is 65891415118.

It can be written as a sum of positive squares in 4 ways, for example, as 28987456 + 81122432400 = 5384^2 + 284820^2 .

It is a congruent number.

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, 558141 + ... + 688348.

It is an arithmetic number, because the mean of its divisors is an integer number (4246666781).

Almost surely, 2^81151419856 is an apocalyptic number.

It is an amenable number.

81151419856 is an abundant number, since it is smaller than the sum of its proper divisors (88715251384).

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

81151419856 is a wasteful number, since it uses less digits than its factorization.

81151419856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1246823 (or 1246817 counting only the distinct ones).

The product of its digits is 345600, while the sum is 49.

The spelling of 81151419856 in words is "eighty-one billion, one hundred fifty-one million, four hundred nineteen thousand, eight hundred fifty-six".