81685227574 has 4 divisors (see below), whose sum is σ = 122527841364. Its totient is φ = 40842613786.

The previous prime is 81685227541. The next prime is 81685227593. The reversal of 81685227574 is 47572258618.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20421306892 + ... + 20421306895.

It is an arithmetic number, because the mean of its divisors is an integer number (30631960341).

Almost surely, 2^81685227574 is an apocalyptic number.

81685227574 is a deficient number, since it is larger than the sum of its proper divisors (40842613790).

81685227574 is a wasteful number, since it uses less digits than its factorization.

81685227574 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40842613789.

The product of its digits is 7526400, while the sum is 55.

The spelling of 81685227574 in words is "eighty-one billion, six hundred eighty-five million, two hundred twenty-seven thousand, five hundred seventy-four".