81933555685 has 8 divisors (see below), whose sum is σ = 100175366520. Its totient is φ = 64310111424.

The previous prime is 81933555677. The next prime is 81933555703. The reversal of 81933555685 is 58655533918.

It can be written as a sum of positive squares in 4 ways, for example, as 23928686721 + 58004868964 = 154689^2 + 240842^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 81933555685 - 2³ = 81933555677 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 154591350 + ... + 154591879.

It is an arithmetic number, because the mean of its divisors is an integer number (12521920815).

Almost surely, 2^81933555685 is an apocalyptic number.

It is an amenable number.

81933555685 is a deficient number, since it is larger than the sum of its proper divisors (18241810835).

81933555685 is a wasteful number, since it uses less digits than its factorization.

81933555685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309183287.

The product of its digits is 19440000, while the sum is 58.

The spelling of 81933555685 in words is "eighty-one billion, nine hundred thirty-three million, five hundred fifty-five thousand, six hundred eighty-five".