81485226749 has 4 divisors (see below), whose sum is σ = 82080009564. Its totient is φ = 80890443936.

The previous prime is 81485226737. The next prime is 81485226787. The reversal of 81485226749 is 94762258418.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 94762258418 = 2 ⋅47381129209.

It can be written as a sum of positive squares in 2 ways, for example, as 30736401124 + 50748825625 = 175318^2 + 225275^2 .

It is a cyclic number.

It is not a de Polignac number, because 81485226749 - 2¹² = 81485222653 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81485226694 and 81485226703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81485220749) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 297391202 + ... + 297391475.

It is an arithmetic number, because the mean of its divisors is an integer number (20520002391).

Almost surely, 2^81485226749 is an apocalyptic number.

It is an amenable number.

81485226749 is a deficient number, since it is larger than the sum of its proper divisors (594782815).

81485226749 is a wasteful number, since it uses less digits than its factorization.

81485226749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 594782814.

The product of its digits is 7741440, while the sum is 56.

The spelling of 81485226749 in words is "eighty-one billion, four hundred eighty-five million, two hundred twenty-six thousand, seven hundred forty-nine".