81815765203 has 4 divisors (see below), whose sum is σ = 81817394368. Its totient is φ = 81814136040.

The previous prime is 81815765197. The next prime is 81815765219. The reversal of 81815765203 is 30256751818.

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 81815765203 - 2⁹ = 81815764691 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81815760203) 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, 736776 + ... + 840517.

It is an arithmetic number, because the mean of its divisors is an integer number (20454348592).

Almost surely, 2^81815765203 is an apocalyptic number.

81815765203 is a deficient number, since it is larger than the sum of its proper divisors (1629165).

81815765203 is a wasteful number, since it uses less digits than its factorization.

81815765203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1629164.

The product of its (nonzero) digits is 403200, while the sum is 46.

The spelling of 81815765203 in words is "eighty-one billion, eight hundred fifteen million, seven hundred sixty-five thousand, two hundred three".