39987217 has 2 divisors, whose sum is σ = 39987218. Its totient is φ = 39987216.

The previous prime is 39987203. The next prime is 39987221. The reversal of 39987217 is 71278993.

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., 26378496 + 13608721 = 5136^2 + 3689^2 .

It is a cyclic number.

It is not a de Polignac number, because 39987217 - 2⁷ = 39987089 is a prime.

It is not a weakly prime, because it can be changed into another prime (39987817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19993608 + 19993609.

It is an arithmetic number, because the mean of its divisors is an integer number (19993609).

Almost surely, 2^39987217 is an apocalyptic number.

It is an amenable number.

39987217 is a deficient number, since it is larger than the sum of its proper divisors (1).

39987217 is an equidigital number, since it uses as much as digits as its factorization.

39987217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 190512, while the sum is 46.

The square root of 39987217 is about 6323.5446547012. The cubic root of 39987217 is about 341.9587544163.

It can be divided in two parts, 39987 and 217, that added together give a palindrome (40204).

The spelling of 39987217 in words is "thirty-nine million, nine hundred eighty-seven thousand, two hundred seventeen".