15805997 has 2 divisors, whose sum is σ = 15805998. Its totient is φ = 15805996.

The previous prime is 15805987. The next prime is 15806003. The reversal of 15805997 is 79950851.

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., 14092516 + 1713481 = 3754^2 + 1309^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15805997 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15805927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7902998 + 7902999.

It is an arithmetic number, because the mean of its divisors is an integer number (7902999).

Almost surely, 2^15805997 is an apocalyptic number.

It is an amenable number.

15805997 is a deficient number, since it is larger than the sum of its proper divisors (1).

15805997 is an equidigital number, since it uses as much as digits as its factorization.

15805997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 113400, while the sum is 44.

The square root of 15805997 is about 3975.6756658460. The cubic root of 15805997 is about 250.9616137866.

The spelling of 15805997 in words is "fifteen million, eight hundred five thousand, nine hundred ninety-seven".