81213057326 has 4 divisors (see below), whose sum is σ = 121819585992. Its totient is φ = 40606528662.

The previous prime is 81213057307. The next prime is 81213057347. The reversal of 81213057326 is 62375031218.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 81213057326.

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 as a sum of consecutive naturals, namely, 20303264330 + ... + 20303264333.

It is an arithmetic number, because the mean of its divisors is an integer number (30454896498).

Almost surely, 2^81213057326 is an apocalyptic number.

81213057326 is a deficient number, since it is larger than the sum of its proper divisors (40606528666).

81213057326 is a wasteful number, since it uses less digits than its factorization.

81213057326 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40606528665.

The product of its (nonzero) digits is 60480, while the sum is 38.

The spelling of 81213057326 in words is "eighty-one billion, two hundred thirteen million, fifty-seven thousand, three hundred twenty-six".