81542248799 has 4 divisors (see below), whose sum is σ = 88955180520. Its totient is φ = 74129317080.

The previous prime is 81542248783. The next prime is 81542248819. The reversal of 81542248799 is 99784224518.

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 81542248799 - 2⁴ = 81542248783 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 (81542248729) 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, 3706465844 + ... + 3706465865.

It is an arithmetic number, because the mean of its divisors is an integer number (22238795130).

Almost surely, 2^81542248799 is an apocalyptic number.

81542248799 is a deficient number, since it is larger than the sum of its proper divisors (7412931721).

81542248799 is a wasteful number, since it uses less digits than its factorization.

81542248799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7412931720.

The product of its digits is 11612160, while the sum is 59.

The spelling of 81542248799 in words is "eighty-one billion, five hundred forty-two million, two hundred forty-eight thousand, seven hundred ninety-nine".