81742413857 has 4 divisors (see below), whose sum is σ = 88030291860. Its totient is φ = 75454535856.

The previous prime is 81742413853. The next prime is 81742413881. The reversal of 81742413857 is 75831424718.

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

It can be written as a sum of positive squares in 2 ways, for example, as 16119857296 + 65622556561 = 126964^2 + 256169^2 .

It is a cyclic number.

It is not a de Polignac number, because 81742413857 - 2² = 81742413853 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81742413853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3143938982 + ... + 3143939007.

It is an arithmetic number, because the mean of its divisors is an integer number (22007572965).

Almost surely, 2^81742413857 is an apocalyptic number.

It is an amenable number.

81742413857 is a deficient number, since it is larger than the sum of its proper divisors (6287878003).

81742413857 is a wasteful number, since it uses less digits than its factorization.

81742413857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6287878002.

The product of its digits is 1505280, while the sum is 50.

The spelling of 81742413857 in words is "eighty-one billion, seven hundred forty-two million, four hundred thirteen thousand, eight hundred fifty-seven".