81634204089 has 9 divisors (see below), whose sum is σ = 117917310693. Its totient is φ = 54422231292.

The previous prime is 81634204087. The next prime is 81634204139. The reversal of 81634204089 is 98040243618.

It is a happy number.

The square root of 81634204089 is 285717.

It is a perfect power (a square), and thus also a powerful number.

81634204089 is a `hidden beast` number, since 8 + 1 + 634 + 2 + 0 + 4 + 0 + 8 + 9 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 81634204089 - 2¹ = 81634204087 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81634204081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 809532 + ... + 904770.

Almost surely, 2^81634204089 is an apocalyptic number.

81634204089 is the 285717-th square number.

81634204089 is the 142859-th centered octagonal number.

It is an amenable number.

81634204089 is a deficient number, since it is larger than the sum of its proper divisors (36283106604).

81634204089 is an frugal number, since it uses more digits than its factorization.

81634204089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190484 (or 95242 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 45.

The spelling of 81634204089 in words is "eighty-one billion, six hundred thirty-four million, two hundred four thousand, eighty-nine".