81135416441 has 4 divisors (see below), whose sum is σ = 83328265572. Its totient is φ = 78942567312.

The previous prime is 81135416419. The next prime is 81135416473. The reversal of 81135416441 is 14461453118.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 63049201216 + 18086215225 = 251096^2 + 134485^2 .

It is a cyclic number.

It is not a de Polignac number, because 81135416441 - 2¹⁴ = 81135400057 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81135416395 and 81135416404.

It is not an unprimeable number, because it can be changed into a prime (81135416041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1096424510 + ... + 1096424583.

It is an arithmetic number, because the mean of its divisors is an integer number (20832066393).

Almost surely, 2^81135416441 is an apocalyptic number.

It is an amenable number.

81135416441 is a deficient number, since it is larger than the sum of its proper divisors (2192849131).

81135416441 is a wasteful number, since it uses less digits than its factorization.

81135416441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2192849130.

The product of its digits is 46080, while the sum is 38.

Adding to 81135416441 its reverse (14461453118), we get a palindrome (95596869559).

The spelling of 81135416441 in words is "eighty-one billion, one hundred thirty-five million, four hundred sixteen thousand, four hundred forty-one".