81979289494 has 32 divisors (see below), whose sum is σ = 127356312960. Its totient is φ = 39555489792.

The previous prime is 81979289473. The next prime is 81979289527. The reversal of 81979289494 is 49498297918.

It is a congruent number.

It is an unprimeable number.

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, 2030052 + ... + 2070040.

It is an arithmetic number, because the mean of its divisors is an integer number (3979884780).

Almost surely, 2^81979289494 is an apocalyptic number.

81979289494 is a deficient number, since it is larger than the sum of its proper divisors (45377023466).

81979289494 is a wasteful number, since it uses less digits than its factorization.

81979289494 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40344.

The product of its digits is 94058496, while the sum is 70.

The spelling of 81979289494 in words is "eighty-one billion, nine hundred seventy-nine million, two hundred eighty-nine thousand, four hundred ninety-four".