81156820803 has 8 divisors (see below), whose sum is σ = 108220382400. Its totient is φ = 54098903208.

The previous prime is 81156820781. The next prime is 81156820807. The reversal of 81156820803 is 30802865118.

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

It is not a de Polignac number, because 81156820803 - 2¹⁴ = 81156804419 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81156820807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1377333 + ... + 1435046.

It is an arithmetic number, because the mean of its divisors is an integer number (13527547800).

Almost surely, 2^81156820803 is an apocalyptic number.

81156820803 is a deficient number, since it is larger than the sum of its proper divisors (27063561597).

81156820803 is a wasteful number, since it uses less digits than its factorization.

81156820803 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2822001.

The product of its (nonzero) digits is 92160, while the sum is 42.

The spelling of 81156820803 in words is "eighty-one billion, one hundred fifty-six million, eight hundred twenty thousand, eight hundred three".