81818701505 has 8 divisors (see below), whose sum is σ = 100034941032. Its totient is φ = 64219961728.

The previous prime is 81818701487. The next prime is 81818701511. The reversal of 81818701505 is 50510781818.

It can be written as a sum of positive squares in 4 ways, for example, as 3398540209 + 78420161296 = 58297^2 + 280036^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81818701505 - 2⁸ = 81818701249 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 154374644 + ... + 154375173.

It is an arithmetic number, because the mean of its divisors is an integer number (12504367629).

Almost surely, 2^81818701505 is an apocalyptic number.

It is an amenable number.

81818701505 is a deficient number, since it is larger than the sum of its proper divisors (18216239527).

81818701505 is a wasteful number, since it uses less digits than its factorization.

81818701505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308749875.

The product of its (nonzero) digits is 89600, while the sum is 44.

The spelling of 81818701505 in words is "eighty-one billion, eight hundred eighteen million, seven hundred one thousand, five hundred five".