81989304443 has 4 divisors (see below), whose sum is σ = 82615177128. Its totient is φ = 81363431760.

The previous prime is 81989304427. The next prime is 81989304451. The reversal of 81989304443 is 34440398918.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34440398918 = 2 ⋅17220199459.

It is a cyclic number.

It is not a de Polignac number, because 81989304443 - 2⁴ = 81989304427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81989304343) 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, 312936146 + ... + 312936407.

It is an arithmetic number, because the mean of its divisors is an integer number (20653794282).

Almost surely, 2^81989304443 is an apocalyptic number.

81989304443 is a deficient number, since it is larger than the sum of its proper divisors (625872685).

81989304443 is a wasteful number, since it uses less digits than its factorization.

81989304443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 625872684.

The product of its (nonzero) digits is 2985984, while the sum is 53.

The spelling of 81989304443 in words is "eighty-one billion, nine hundred eighty-nine million, three hundred four thousand, four hundred forty-three".