81385866606 has 32 divisors (see below), whose sum is σ = 188014411008. Its totient is φ = 23211655040.

The previous prime is 81385866593. The next prime is 81385866607. The reversal of 81385866606 is 60666858318.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81385866607) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36267090 + ... + 36269333.

It is an arithmetic number, because the mean of its divisors is an integer number (5875450344).

Almost surely, 2^81385866606 is an apocalyptic number.

81385866606 is an abundant number, since it is smaller than the sum of its proper divisors (106628544402).

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

81385866606 is a wasteful number, since it uses less digits than its factorization.

81385866606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72536456.

The product of its (nonzero) digits is 9953280, while the sum is 57.

The spelling of 81385866606 in words is "eighty-one billion, three hundred eighty-five million, eight hundred sixty-six thousand, six hundred six".