81209456663 has 2 divisors, whose sum is σ = 81209456664. Its totient is φ = 81209456662.

The previous prime is 81209456617. The next prime is 81209456701. The reversal of 81209456663 is 36665490218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81209456663 - 2¹⁶ = 81209391127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81209456863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40604728331 + 40604728332.

It is an arithmetic number, because the mean of its divisors is an integer number (40604728332).

Almost surely, 2^81209456663 is an apocalyptic number.

81209456663 is a deficient number, since it is larger than the sum of its proper divisors (1).

81209456663 is an equidigital number, since it uses as much as digits as its factorization.

81209456663 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1866240, while the sum is 50.

The spelling of 81209456663 in words is "eighty-one billion, two hundred nine million, four hundred fifty-six thousand, six hundred sixty-three".