81251351497 has 2 divisors, whose sum is σ = 81251351498. Its totient is φ = 81251351496.

The previous prime is 81251351429. The next prime is 81251351507. The reversal of 81251351497 is 79415315218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80734971321 + 516380176 = 284139^2 + 22724^2 .

It is a cyclic number.

It is not a de Polignac number, because 81251351497 - 2¹¹ = 81251349449 is a prime.

It is not a weakly prime, because it can be changed into another prime (81251351407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40625675748 + 40625675749.

It is an arithmetic number, because the mean of its divisors is an integer number (40625675749).

Almost surely, 2^81251351497 is an apocalyptic number.

It is an amenable number.

81251351497 is a deficient number, since it is larger than the sum of its proper divisors (1).

81251351497 is an equidigital number, since it uses as much as digits as its factorization.

81251351497 is an evil number, because the sum of its binary digits is even.

The product of its digits is 302400, while the sum is 46.

The spelling of 81251351497 in words is "eighty-one billion, two hundred fifty-one million, three hundred fifty-one thousand, four hundred ninety-seven".