81548664551 has 2 divisors, whose sum is σ = 81548664552. Its totient is φ = 81548664550.

The previous prime is 81548664541. The next prime is 81548664559. The reversal of 81548664551 is 15546684518.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81548664551 - 2¹⁸ = 81548402407 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81548664493 and 81548664502.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81548664559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40774332275 + 40774332276.

It is an arithmetic number, because the mean of its divisors is an integer number (40774332276).

Almost surely, 2^81548664551 is an apocalyptic number.

81548664551 is a deficient number, since it is larger than the sum of its proper divisors (1).

81548664551 is an equidigital number, since it uses as much as digits as its factorization.

81548664551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4608000, while the sum is 53.

The spelling of 81548664551 in words is "eighty-one billion, five hundred forty-eight million, six hundred sixty-four thousand, five hundred fifty-one".