81490185216 has 352 divisors, whose sum is σ = 268922741760. Its totient is φ = 24164352000.

The previous prime is 81490185193. The next prime is 81490185229. The reversal of 81490185216 is 61258109418.

It is a happy number.

81490185216 is a `hidden beast` number, since 81 + 49 + 0 + 1 + 8 + 521 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (352).

It is an alternating number because its digits alternate between even and odd.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14291166 + ... + 14296866.

Almost surely, 2^81490185216 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 81490185216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134461370880).

81490185216 is an abundant number, since it is smaller than the sum of its proper divisors (187432556544).

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

81490185216 is a wasteful number, since it uses less digits than its factorization.

81490185216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5788 (or 5764 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 45.

The spelling of 81490185216 in words is "eighty-one billion, four hundred ninety million, one hundred eighty-five thousand, two hundred sixteen".