81513843 has 4 divisors (see below), whose sum is σ = 108685128. Its totient is φ = 54342560.

The previous prime is 81513829. The next prime is 81513881. The reversal of 81513843 is 34831518.

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 81513843 - 2⁵ = 81513811 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81513343) 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 3 ways as a sum of consecutive naturals, for example, 13585638 + ... + 13585643.

It is an arithmetic number, because the mean of its divisors is an integer number (27171282).

Almost surely, 2^81513843 is an apocalyptic number.

81513843 is a deficient number, since it is larger than the sum of its proper divisors (27171285).

81513843 is a wasteful number, since it uses less digits than its factorization.

81513843 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27171284.

The product of its digits is 11520, while the sum is 33.

The square root of 81513843 is about 9028.5017029405. The cubic root of 81513843 is about 433.5878689338.

The spelling of 81513843 in words is "eighty-one million, five hundred thirteen thousand, eight hundred forty-three".