39809999 has 2 divisors, whose sum is σ = 39810000. Its totient is φ = 39809998.

The previous prime is 39809989. The next prime is 39810007. The reversal of 39809999 is 99990893.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (99990893) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 39809999 - 2¹² = 39805903 is a prime.

39809999 is a modest number, since divided by 9999 gives 3980 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (39809929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19904999 + 19905000.

It is an arithmetic number, because the mean of its divisors is an integer number (19905000).

Almost surely, 2^39809999 is an apocalyptic number.

39809999 is a deficient number, since it is larger than the sum of its proper divisors (1).

39809999 is an equidigital number, since it uses as much as digits as its factorization.

39809999 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1417176, while the sum is 56.

The square root of 39809999 is about 6309.5165424936. The cubic root of 39809999 is about 341.4528344606.

The spelling of 39809999 in words is "thirty-nine million, eight hundred nine thousand, nine hundred ninety-nine".