81021970803 has 16 divisors (see below), whose sum is σ = 109551149856. Its totient is φ = 53254287360.

The previous prime is 81021970801. The next prime is 81021970823. The reversal of 81021970803 is 30807912018.

It is not a de Polignac number, because 81021970803 - 2¹ = 81021970801 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81021970801) 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 15 ways as a sum of consecutive naturals, for example, 512263 + ... + 651503.

It is an arithmetic number, because the mean of its divisors is an integer number (6846946866).

Almost surely, 2^81021970803 is an apocalyptic number.

81021970803 is a deficient number, since it is larger than the sum of its proper divisors (28529179053).

81021970803 is a wasteful number, since it uses less digits than its factorization.

81021970803 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141974.

The product of its (nonzero) digits is 24192, while the sum is 39.

The spelling of 81021970803 in words is "eighty-one billion, twenty-one million, nine hundred seventy thousand, eight hundred three".