19999739 has 2 divisors, whose sum is σ = 19999740. Its totient is φ = 19999738.

The previous prime is 19999729. The next prime is 19999789. The reversal of 19999739 is 93799991.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19999739 - 2¹² = 19995643 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19999729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9999869 + 9999870.

It is an arithmetic number, because the mean of its divisors is an integer number (9999870).

Almost surely, 2^19999739 is an apocalyptic number.

19999739 is a deficient number, since it is larger than the sum of its proper divisors (1).

19999739 is an equidigital number, since it uses as much as digits as its factorization.

19999739 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1240029, while the sum is 56.

The square root of 19999739 is about 4472.1067742173. The cubic root of 19999739 is about 271.4405808827.

The spelling of 19999739 in words is "nineteen million, nine hundred ninety-nine thousand, seven hundred thirty-nine".