81838413612505 has 8 divisors (see below), whose sum is σ = 107133923274624. Its totient is φ = 59518846263600.

The previous prime is 81838413612497. The next prime is 81838413612523. The reversal of 81838413612505 is 50521631483818.

It is a happy number.

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

It is not a de Polignac number, because 81838413612505 - 2³ = 81838413612497 is a prime.

It is a super-2 number, since 2×81838413612505² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (55), and also a Moran number because the ratio is a prime number: 1487971156591 = 81838413612505 / (8 + 1 + 8 + 3 + 8 + 4 + 1 + 3 + 6 + 1 + 2 + 5 + 0 + 5).

It is a Duffinian 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, 743985578241 + ... + 743985578350.

It is an arithmetic number, because the mean of its divisors is an integer number (13391740409328).

Almost surely, 2^{81838413612505} is an apocalyptic number.

It is an amenable number.

81838413612505 is a deficient number, since it is larger than the sum of its proper divisors (25295509662119).

81838413612505 is a wasteful number, since it uses less digits than its factorization.

81838413612505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1487971156607.

The product of its (nonzero) digits is 5529600, while the sum is 55.

The spelling of 81838413612505 in words is "eighty-one trillion, eight hundred thirty-eight billion, four hundred thirteen million, six hundred twelve thousand, five hundred five".