81653633489 has 2 divisors, whose sum is σ = 81653633490. Its totient is φ = 81653633488.

The previous prime is 81653633459. The next prime is 81653633519. The reversal of 81653633489 is 98433635618.

It is a balanced prime because it is at equal distance from previous prime (81653633459) and next prime (81653633519).

It can be written as a sum of positive squares in only one way, i.e., 60130396225 + 21523237264 = 245215^2 + 146708^2 .

It is a cyclic number.

It is not a de Polignac number, because 81653633489 - 2²⁰ = 81652584913 is a prime.

It is not a weakly prime, because it can be changed into another prime (81653633459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40826816744 + 40826816745.

It is an arithmetic number, because the mean of its divisors is an integer number (40826816745).

Almost surely, 2^81653633489 is an apocalyptic number.

It is an amenable number.

81653633489 is a deficient number, since it is larger than the sum of its proper divisors (1).

81653633489 is an equidigital number, since it uses as much as digits as its factorization.

81653633489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11197440, while the sum is 56.

The spelling of 81653633489 in words is "eighty-one billion, six hundred fifty-three million, six hundred thirty-three thousand, four hundred eighty-nine".