81228989979 has 6 divisors (see below), whose sum is σ = 117330763316. Its totient is φ = 54152659980.

The previous prime is 81228989923. The next prime is 81228989983. The reversal of 81228989979 is 97998982218.

It is not a de Polignac number, because 81228989979 - 2¹³ = 81228981787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81228989579) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4512721657 + ... + 4512721674.

Almost surely, 2^81228989979 is an apocalyptic number.

81228989979 is a deficient number, since it is larger than the sum of its proper divisors (36101773337).

81228989979 is a wasteful number, since it uses less digits than its factorization.

81228989979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9025443337 (or 9025443334 counting only the distinct ones).

The product of its digits is 94058496, while the sum is 72.

The spelling of 81228989979 in words is "eighty-one billion, two hundred twenty-eight million, nine hundred eighty-nine thousand, nine hundred seventy-nine".