81325759997 has 2 divisors, whose sum is σ = 81325759998. Its totient is φ = 81325759996.

The previous prime is 81325759951. The next prime is 81325760069. The reversal of 81325759997 is 79995752318.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 79530204121 + 1795555876 = 282011^2 + 42374^2 .

It is a cyclic number.

It is not a de Polignac number, because 81325759997 - 2³⁰ = 80252018173 is a prime.

It is a super-2 number, since 2×81325759997² (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 (81325759937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40662879998 + 40662879999.

It is an arithmetic number, because the mean of its divisors is an integer number (40662879999).

Almost surely, 2^81325759997 is an apocalyptic number.

It is an amenable number.

81325759997 is a deficient number, since it is larger than the sum of its proper divisors (1).

81325759997 is an equidigital number, since it uses as much as digits as its factorization.

81325759997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 42865200, while the sum is 65.

The spelling of 81325759997 in words is "eighty-one billion, three hundred twenty-five million, seven hundred fifty-nine thousand, nine hundred ninety-seven".