81493095557 has 32 divisors (see below), whose sum is σ = 85184736000. Its totient is φ = 77906188800.

The previous prime is 81493095539. The next prime is 81493095559. The reversal of 81493095557 is 75559039418.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 81493095557 - 2¹⁰ = 81493094533 is a prime.

It is a super-2 number, since 2×81493095557² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81493095559) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 205272083 + ... + 205272479.

It is an arithmetic number, because the mean of its divisors is an integer number (2662023000).

Almost surely, 2^81493095557 is an apocalyptic number.

It is an amenable number.

81493095557 is a deficient number, since it is larger than the sum of its proper divisors (3691640443).

81493095557 is a wasteful number, since it uses less digits than its factorization.

81493095557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 957.

The product of its (nonzero) digits is 6804000, while the sum is 56.

The spelling of 81493095557 in words is "eighty-one billion, four hundred ninety-three million, ninety-five thousand, five hundred fifty-seven".