81669973655 has 8 divisors (see below), whose sum is σ = 98628198432. Its totient is φ = 64919825568.

The previous prime is 81669973643. The next prime is 81669973661. The reversal of 81669973655 is 55637996618.

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 81669973655 - 2¹⁶ = 81669908119 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81669973591 and 81669973600.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52018307 + ... + 52019876.

It is an arithmetic number, because the mean of its divisors is an integer number (12328524804).

Almost surely, 2^81669973655 is an apocalyptic number.

81669973655 is a deficient number, since it is larger than the sum of its proper divisors (16958224777).

81669973655 is a wasteful number, since it uses less digits than its factorization.

81669973655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104038345.

The product of its digits is 73483200, while the sum is 65.

The spelling of 81669973655 in words is "eighty-one billion, six hundred sixty-nine million, nine hundred seventy-three thousand, six hundred fifty-five".