81204908181 has 16 divisors (see below), whose sum is σ = 108487833408. Its totient is φ = 54029360000.

The previous prime is 81204908179. The next prime is 81204908233. The reversal of 81204908181 is 18180940218.

It is a cyclic number.

It is not a de Polignac number, because 81204908181 - 2¹ = 81204908179 is a prime.

It is a super-2 number, since 2×81204908181² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81204908111) 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, 6622306 + ... + 6634556.

It is an arithmetic number, because the mean of its divisors is an integer number (6780489588).

Almost surely, 2^81204908181 is an apocalyptic number.

It is an amenable number.

81204908181 is a deficient number, since it is larger than the sum of its proper divisors (27282925227).

81204908181 is a wasteful number, since it uses less digits than its factorization.

81204908181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16452.

The product of its (nonzero) digits is 36864, while the sum is 42.

The spelling of 81204908181 in words is "eighty-one billion, two hundred four million, nine hundred eight thousand, one hundred eighty-one".