81413808345 has 20 divisors (see below), whose sum is σ = 145941790500. Its totient is φ = 43420697568.

The previous prime is 81413808319. The next prime is 81413808361. The reversal of 81413808345 is 54380831418.

81413808345 is a `hidden beast` number, since 81 + 413 + 80 + 83 + 4 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 55873613376 + 25540194969 = 236376^2 + 159813^2 .

It is not a de Polignac number, because 81413808345 - 2¹¹ = 81413806297 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81413808345.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 100510470 + ... + 100511279.

It is an arithmetic number, because the mean of its divisors is an integer number (7297089525).

Almost surely, 2^81413808345 is an apocalyptic number.

It is an amenable number.

81413808345 is a deficient number, since it is larger than the sum of its proper divisors (64527982155).

81413808345 is a wasteful number, since it uses less digits than its factorization.

81413808345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201021766 (or 201021757 counting only the distinct ones).

The product of its (nonzero) digits is 368640, while the sum is 45.

The spelling of 81413808345 in words is "eighty-one billion, four hundred thirteen million, eight hundred eight thousand, three hundred forty-five".