81542859 has 4 divisors (see below), whose sum is σ = 108723816. Its totient is φ = 54361904.

The previous prime is 81542833. The next prime is 81542873. The reversal of 81542859 is 95824518.

It is a happy number.

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 81542859 - 2⁹ = 81542347 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81542859.

It is not an unprimeable number, because it can be changed into a prime (81542159) 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, 13590474 + ... + 13590479.

It is an arithmetic number, because the mean of its divisors is an integer number (27180954).

Almost surely, 2^81542859 is an apocalyptic number.

81542859 is a deficient number, since it is larger than the sum of its proper divisors (27180957).

81542859 is a wasteful number, since it uses less digits than its factorization.

81542859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27180956.

The product of its digits is 115200, while the sum is 42.

The square root of 81542859 is about 9030.1084711093. The cubic root of 81542859 is about 433.6393100659.

The spelling of 81542859 in words is "eighty-one million, five hundred forty-two thousand, eight hundred fifty-nine".