81118444969 has 3 divisors (see below), whose sum is σ = 81118729783. Its totient is φ = 81118160156.

The previous prime is 81118444963. The next prime is 81118444991. The reversal of 81118444969 is 96944481118.

The square root of 81118444969 is 284813.

It is a perfect power (a square), and thus also a powerful number.

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 can be written as a sum of positive squares in only one way, i.e., 3172505625 + 77945939344 = 56325^2 + 279188^2 .

It is not a de Polignac number, because 81118444969 - 2⁹ = 81118444457 is a prime.

It is a super-2 number, since 2×81118444969² (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 (81118444963) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 142407 + ... + 427219.

Almost surely, 2^81118444969 is an apocalyptic number.

81118444969 is the 284813-rd square number.

81118444969 is the 142407-th centered octagonal number.

It is an amenable number.

81118444969 is a deficient number, since it is larger than the sum of its proper divisors (284814).

81118444969 is an frugal number, since it uses more digits than its factorization.

81118444969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 569626 (or 284813 counting only the distinct ones).

The product of its digits is 1990656, while the sum is 55.

The spelling of 81118444969 in words is "eighty-one billion, one hundred eighteen million, four hundred forty-four thousand, nine hundred sixty-nine".