39978539 has 2 divisors, whose sum is σ = 39978540. Its totient is φ = 39978538.

The previous prime is 39978493. The next prime is 39978541. The reversal of 39978539 is 93587993.

It is a strong prime.

It is an emirp because it is prime and its reverse (93587993) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 39978539 - 2⁸ = 39978283 is a prime.

It is a Sophie Germain prime.

Together with 39978541, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (39978139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19989269 + 19989270.

It is an arithmetic number, because the mean of its divisors is an integer number (19989270).

Almost surely, 2^39978539 is an apocalyptic number.

39978539 is a deficient number, since it is larger than the sum of its proper divisors (1).

39978539 is an equidigital number, since it uses as much as digits as its factorization.

39978539 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1837080, while the sum is 53.

The square root of 39978539 is about 6322.8584516815. The cubic root of 39978539 is about 341.9340154039.

The spelling of 39978539 in words is "thirty-nine million, nine hundred seventy-eight thousand, five hundred thirty-nine".