81693147646 has 32 divisors (see below), whose sum is σ = 135318076416. Its totient is φ = 36679860000.

The previous prime is 81693147629. The next prime is 81693147719. The reversal of 81693147646 is 64674139618.

It is a super-2 number, since 2×81693147646² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 915031 + ... + 1000333.

It is an arithmetic number, because the mean of its divisors is an integer number (4228689888).

Almost surely, 2^81693147646 is an apocalyptic number.

81693147646 is a deficient number, since it is larger than the sum of its proper divisors (53624928770).

81693147646 is a wasteful number, since it uses less digits than its factorization.

81693147646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85848.

The product of its digits is 5225472, while the sum is 55.

The spelling of 81693147646 in words is "eighty-one billion, six hundred ninety-three million, one hundred forty-seven thousand, six hundred forty-six".