19807939 has 2 divisors, whose sum is σ = 19807940. Its totient is φ = 19807938.

The previous prime is 19807919. The next prime is 19807967. The reversal of 19807939 is 93970891.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19807939 is a prime.

It is not a weakly prime, because it can be changed into another prime (19807919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9903969 + 9903970.

It is an arithmetic number, because the mean of its divisors is an integer number (9903970).

Almost surely, 2^19807939 is an apocalyptic number.

19807939 is a deficient number, since it is larger than the sum of its proper divisors (1).

19807939 is an equidigital number, since it uses as much as digits as its factorization.

19807939 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 122472, while the sum is 46.

The square root of 19807939 is about 4450.6110816381. The cubic root of 19807939 is about 270.5700757921.

The spelling of 19807939 in words is "nineteen million, eight hundred seven thousand, nine hundred thirty-nine".