81234777131 has 4 divisors (see below), whose sum is σ = 81247241064. Its totient is φ = 81222313200.

The previous prime is 81234777101. The next prime is 81234777137. The reversal of 81234777131 is 13177743218.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13177743218 = 2 ⋅6588871609.

It is a cyclic number.

It is not a de Polignac number, because 81234777131 - 2¹⁰ = 81234776107 is a prime.

It is a super-2 number, since 2×81234777131² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81234777137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6222185 + ... + 6235226.

It is an arithmetic number, because the mean of its divisors is an integer number (20311810266).

Almost surely, 2^81234777131 is an apocalyptic number.

81234777131 is a deficient number, since it is larger than the sum of its proper divisors (12463933).

81234777131 is a wasteful number, since it uses less digits than its factorization.

81234777131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12463932.

The product of its digits is 197568, while the sum is 44.

The spelling of 81234777131 in words is "eighty-one billion, two hundred thirty-four million, seven hundred seventy-seven thousand, one hundred thirty-one".