81697597447 has 2 divisors, whose sum is σ = 81697597448. Its totient is φ = 81697597446.

The previous prime is 81697597417. The next prime is 81697597519. The reversal of 81697597447 is 74479579618.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81697597447 is a prime.

It is a super-2 number, since 2×81697597447² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81697597417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40848798723 + 40848798724.

It is an arithmetic number, because the mean of its divisors is an integer number (40848798724).

Almost surely, 2^81697597447 is an apocalyptic number.

81697597447 is a deficient number, since it is larger than the sum of its proper divisors (1).

81697597447 is an equidigital number, since it uses as much as digits as its factorization.

81697597447 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 106686720, while the sum is 67.

The spelling of 81697597447 in words is "eighty-one billion, six hundred ninety-seven million, five hundred ninety-seven thousand, four hundred forty-seven".