81493818519 has 8 divisors (see below), whose sum is σ = 108894128112. Its totient is φ = 54211360640.

The previous prime is 81493818503. The next prime is 81493818557. The reversal of 81493818519 is 91581839418.

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 81493818519 - 2⁴ = 81493818503 is a prime.

It is a super-2 number, since 2×81493818519² (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 (81493818589) 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, 29461314 + ... + 29464079.

It is an arithmetic number, because the mean of its divisors is an integer number (13611766014).

Almost surely, 2^81493818519 is an apocalyptic number.

81493818519 is a deficient number, since it is larger than the sum of its proper divisors (27400309593).

81493818519 is a wasteful number, since it uses less digits than its factorization.

81493818519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58925857.

The product of its digits is 2488320, while the sum is 57.

The spelling of 81493818519 in words is "eighty-one billion, four hundred ninety-three million, eight hundred eighteen thousand, five hundred nineteen".