81186897036 has 96 divisors (see below), whose sum is σ = 222341898240. Its totient is φ = 22575691584.

The previous prime is 81186897031. The next prime is 81186897037. The reversal of 81186897036 is 63079868118.

It is not an unprimeable number, because it can be changed into a prime (81186897031) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 649251 + ... + 764133.

It is an arithmetic number, because the mean of its divisors is an integer number (2316061440).

Almost surely, 2^81186897036 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81186897036, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111170949120).

81186897036 is an abundant number, since it is smaller than the sum of its proper divisors (141155001204).

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

81186897036 is a wasteful number, since it uses less digits than its factorization.

81186897036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115123 (or 115121 counting only the distinct ones).

The product of its (nonzero) digits is 3483648, while the sum is 57.

The spelling of 81186897036 in words is "eighty-one billion, one hundred eighty-six million, eight hundred ninety-seven thousand, thirty-six".