81799897 has 2 divisors, whose sum is σ = 81799898. Its totient is φ = 81799896.

The previous prime is 81799877. The next prime is 81799973. The reversal of 81799897 is 79899718.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60047001 + 21752896 = 7749^2 + 4664^2 .

It is a cyclic number.

It is not a de Polignac number, because 81799897 - 2¹⁵ = 81767129 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81799877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40899948 + 40899949.

It is an arithmetic number, because the mean of its divisors is an integer number (40899949).

Almost surely, 2^81799897 is an apocalyptic number.

It is an amenable number.

81799897 is a deficient number, since it is larger than the sum of its proper divisors (1).

81799897 is an equidigital number, since it uses as much as digits as its factorization.

81799897 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2286144, while the sum is 58.

The square root of 81799897 is about 9044.3295495023. The cubic root of 81799897 is about 434.0944689482.

The spelling of 81799897 in words is "eighty-one million, seven hundred ninety-nine thousand, eight hundred ninety-seven".