15997973 has 2 divisors, whose sum is σ = 15997974. Its totient is φ = 15997972.

The previous prime is 15997957. The next prime is 15997979. The reversal of 15997973 is 37979951.

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., 10876804 + 5121169 = 3298^2 + 2263^2 .

It is a cyclic number.

It is not a de Polignac number, because 15997973 - 2⁴ = 15997957 is a prime.

It is a super-3 number, since 3×15997973³ (a number of 23 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15997979) 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, 7998986 + 7998987.

It is an arithmetic number, because the mean of its divisors is an integer number (7998987).

Almost surely, 2^15997973 is an apocalyptic number.

It is an amenable number.

15997973 is a deficient number, since it is larger than the sum of its proper divisors (1).

15997973 is an equidigital number, since it uses as much as digits as its factorization.

15997973 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 535815, while the sum is 50.

The square root of 15997973 is about 3999.7466169746. The cubic root of 15997973 is about 251.9735684464.

The spelling of 15997973 in words is "fifteen million, nine hundred ninety-seven thousand, nine hundred seventy-three".