39917221 has 2 divisors, whose sum is σ = 39917222. Its totient is φ = 39917220.

The previous prime is 39917153. The next prime is 39917239. The reversal of 39917221 is 12271993.

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., 39866596 + 50625 = 6314^2 + 225^2 .

It is a cyclic number.

It is not a de Polignac number, because 39917221 - 2²³ = 31528613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (39917261) 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, 19958610 + 19958611.

It is an arithmetic number, because the mean of its divisors is an integer number (19958611).

Almost surely, 2^39917221 is an apocalyptic number.

It is an amenable number.

39917221 is a deficient number, since it is larger than the sum of its proper divisors (1).

39917221 is an equidigital number, since it uses as much as digits as its factorization.

39917221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6804, while the sum is 34.

The square root of 39917221 is about 6318.0076764752. The cubic root of 39917221 is about 341.7591095752.

The spelling of 39917221 in words is "thirty-nine million, nine hundred seventeen thousand, two hundred twenty-one".