81831669557 has 8 divisors (see below), whose sum is σ = 94522142592. Its totient is φ = 70016401600.

The previous prime is 81831669553. The next prime is 81831669581. The reversal of 81831669557 is 75596613818.

It is a happy number.

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 81831669557 - 2² = 81831669553 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81831669496 and 81831669505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81831669553) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 218801069 + ... + 218801442.

It is an arithmetic number, because the mean of its divisors is an integer number (11815267824).

Almost surely, 2^81831669557 is an apocalyptic number.

It is an amenable number.

81831669557 is a deficient number, since it is larger than the sum of its proper divisors (12690473035).

81831669557 is a wasteful number, since it uses less digits than its factorization.

81831669557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437602539.

The product of its digits is 10886400, while the sum is 59.

The spelling of 81831669557 in words is "eighty-one billion, eight hundred thirty-one million, six hundred sixty-nine thousand, five hundred fifty-seven".