81117697 has 2 divisors, whose sum is σ = 81117698. Its totient is φ = 81117696.

The previous prime is 81117683. The next prime is 81117703. The reversal of 81117697 is 79671118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40972801 + 40144896 = 6401^2 + 6336^2 .

It is a cyclic number.

It is not a de Polignac number, because 81117697 - 2¹⁵ = 81084929 is a prime.

It is not a weakly prime, because it can be changed into another prime (81117097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40558848 + 40558849.

It is an arithmetic number, because the mean of its divisors is an integer number (40558849).

Almost surely, 2^81117697 is an apocalyptic number.

It is an amenable number.

81117697 is a deficient number, since it is larger than the sum of its proper divisors (1).

81117697 is an equidigital number, since it uses as much as digits as its factorization.

81117697 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21168, while the sum is 40.

The square root of 81117697 is about 9006.5363486748. The cubic root of 81117697 is about 432.8843356556.

The spelling of 81117697 in words is "eighty-one million, one hundred seventeen thousand, six hundred ninety-seven".