81247845599 has 4 divisors (see below), whose sum is σ = 81249726000. Its totient is φ = 81245965200.

The previous prime is 81247845593. The next prime is 81247845617. The reversal of 81247845599 is 99554874218.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81247845599 - 2¹⁶ = 81247780063 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81247845593) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 873827 + ... + 962324.

It is an arithmetic number, because the mean of its divisors is an integer number (20312431500).

Almost surely, 2^81247845599 is an apocalyptic number.

81247845599 is a deficient number, since it is larger than the sum of its proper divisors (1880401).

81247845599 is a wasteful number, since it uses less digits than its factorization.

81247845599 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1880400.

The product of its digits is 29030400, while the sum is 62.

The spelling of 81247845599 in words is "eighty-one billion, two hundred forty-seven million, eight hundred forty-five thousand, five hundred ninety-nine".