81448249357 has 2 divisors, whose sum is σ = 81448249358. Its totient is φ = 81448249356.

The previous prime is 81448249321. The next prime is 81448249361. The reversal of 81448249357 is 75394284418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61399388521 + 20048860836 = 247789^2 + 141594^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81448249357 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81448249298 and 81448249307.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81448219357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40724124678 + 40724124679.

It is an arithmetic number, because the mean of its divisors is an integer number (40724124679).

Almost surely, 2^81448249357 is an apocalyptic number.

It is an amenable number.

81448249357 is a deficient number, since it is larger than the sum of its proper divisors (1).

81448249357 is an equidigital number, since it uses as much as digits as its factorization.

81448249357 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7741440, while the sum is 55.

The spelling of 81448249357 in words is "eighty-one billion, four hundred forty-eight million, two hundred forty-nine thousand, three hundred fifty-seven".