79991897 has 2 divisors, whose sum is σ = 79991898. Its totient is φ = 79991896.

The previous prime is 79991827. The next prime is 79991917. The reversal of 79991897 is 79819997.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51036736 + 28955161 = 7144^2 + 5381^2 .

It is a cyclic number.

It is not a de Polignac number, because 79991897 - 2¹⁰ = 79990873 is a prime.

It is a super-3 number, since 3×79991897³ (a number of 25 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (79991827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39995948 + 39995949.

It is an arithmetic number, because the mean of its divisors is an integer number (39995949).

Almost surely, 2^79991897 is an apocalyptic number.

It is an amenable number.

79991897 is a deficient number, since it is larger than the sum of its proper divisors (1).

79991897 is an equidigital number, since it uses as much as digits as its factorization.

79991897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2571912, while the sum is 59.

The square root of 79991897 is about 8943.8189270579. The cubic root of 79991897 is about 430.8723896949.

The spelling of 79991897 in words is "seventy-nine million, nine hundred ninety-one thousand, eight hundred ninety-seven".