81138063751 has 4 divisors (see below), whose sum is σ = 81138824512. Its totient is φ = 81137302992.

The previous prime is 81138063661. The next prime is 81138063761. The reversal of 81138063751 is 15736083118.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 81138063751 - 2¹⁷ = 81137932679 is a prime.

It is a super-2 number, since 2×81138063751² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81138063698 and 81138063707.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81138063761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 187950 + ... + 444523.

It is an arithmetic number, because the mean of its divisors is an integer number (20284706128).

Almost surely, 2^81138063751 is an apocalyptic number.

81138063751 is a deficient number, since it is larger than the sum of its proper divisors (760761).

81138063751 is a wasteful number, since it uses less digits than its factorization.

81138063751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 760760.

The product of its (nonzero) digits is 120960, while the sum is 43.

The spelling of 81138063751 in words is "eighty-one billion, one hundred thirty-eight million, sixty-three thousand, seven hundred fifty-one".