81259471780394 has 8 divisors (see below), whose sum is σ = 122967873225540. Its totient is φ = 40270180705216.

The previous prime is 81259471780343. The next prime is 81259471780441. The reversal of 81259471780394 is 49308717495218.

It can be written as a sum of positive squares in 2 ways, for example, as 55487228550625 + 25772243229769 = 7448975^2 + 5076637^2 .

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

It is a super-3 number, since 3×81259471780394³ (a number of 43 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 179777592209 + ... + 179777592660.

Almost surely, 2^{81259471780394} is an apocalyptic number.

81259471780394 is a deficient number, since it is larger than the sum of its proper divisors (41708401445146).

81259471780394 is a wasteful number, since it uses less digits than its factorization.

81259471780394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 359555184984.

The product of its (nonzero) digits is 121927680, while the sum is 68.

The spelling of 81259471780394 in words is "eighty-one trillion, two hundred fifty-nine billion, four hundred seventy-one million, seven hundred eighty thousand, three hundred ninety-four".