81185597 has 2 divisors, whose sum is σ = 81185598. Its totient is φ = 81185596.

The previous prime is 81185581. The next prime is 81185623. The reversal of 81185597 is 79558118.

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., 43375396 + 37810201 = 6586^2 + 6149^2 .

It is a cyclic number.

It is not a de Polignac number, because 81185597 - 2⁴ = 81185581 is a prime.

It is a super-2 number, since 2×81185597² = 13182202320492818, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81182597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40592798 + 40592799.

It is an arithmetic number, because the mean of its divisors is an integer number (40592799).

Almost surely, 2^81185597 is an apocalyptic number.

It is an amenable number.

81185597 is a deficient number, since it is larger than the sum of its proper divisors (1).

81185597 is an equidigital number, since it uses as much as digits as its factorization.

81185597 is an evil number, because the sum of its binary digits is even.

The product of its digits is 100800, while the sum is 44.

The square root of 81185597 is about 9010.3050447807. The cubic root of 81185597 is about 433.0050846830.

The spelling of 81185597 in words is "eighty-one million, one hundred eighty-five thousand, five hundred ninety-seven".