19904789 has 2 divisors, whose sum is σ = 19904790. Its totient is φ = 19904788.

The previous prime is 19904749. The next prime is 19904791. The reversal of 19904789 is 98740991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10510564 + 9394225 = 3242^2 + 3065^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19904789 is a prime.

Together with 19904791, 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 (19904749) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9952394 + 9952395.

It is an arithmetic number, because the mean of its divisors is an integer number (9952395).

Almost surely, 2^19904789 is an apocalyptic number.

It is an amenable number.

19904789 is a deficient number, since it is larger than the sum of its proper divisors (1).

19904789 is an equidigital number, since it uses as much as digits as its factorization.

19904789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 163296, while the sum is 47.

The square root of 19904789 is about 4461.4783424331. The cubic root of 19904789 is about 271.0103389709.

The spelling of 19904789 in words is "nineteen million, nine hundred four thousand, seven hundred eighty-nine".