39378221 has 2 divisors, whose sum is σ = 39378222. Its totient is φ = 39378220.

The previous prime is 39378211. The next prime is 39378223. The reversal of 39378221 is 12287393.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21855625 + 17522596 = 4675^2 + 4186^2 .

It is a cyclic number.

It is not a de Polignac number, because 39378221 - 2²² = 35183917 is a prime.

Together with 39378223, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (39378223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19689110 + 19689111.

It is an arithmetic number, because the mean of its divisors is an integer number (19689111).

Almost surely, 2^39378221 is an apocalyptic number.

It is an amenable number.

39378221 is a deficient number, since it is larger than the sum of its proper divisors (1).

39378221 is an equidigital number, since it uses as much as digits as its factorization.

39378221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 35.

The square root of 39378221 is about 6275.2068491804. The cubic root of 39378221 is about 340.2138821503.

The spelling of 39378221 in words is "thirty-nine million, three hundred seventy-eight thousand, two hundred twenty-one".