81633278443 has 8 divisors (see below), whose sum is σ = 81818506512. Its totient is φ = 81448182816.

The previous prime is 81633278437. The next prime is 81633278449. The reversal of 81633278443 is 34487233618.

It is an interprime number because it is at equal distance from previous prime (81633278437) and next prime (81633278449).

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81633278443 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81633278449) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1257621 + ... + 1320937.

It is an arithmetic number, because the mean of its divisors is an integer number (10227313314).

Almost surely, 2^81633278443 is an apocalyptic number.

81633278443 is a deficient number, since it is larger than the sum of its proper divisors (185228069).

81633278443 is a wasteful number, since it uses less digits than its factorization.

81633278443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66221.

The product of its digits is 2322432, while the sum is 49.

The spelling of 81633278443 in words is "eighty-one billion, six hundred thirty-three million, two hundred seventy-eight thousand, four hundred forty-three".