19994647 has 2 divisors, whose sum is σ = 19994648. Its totient is φ = 19994646.

The previous prime is 19994591. The next prime is 19994657. The reversal of 19994647 is 74649991.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19994647 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19994647.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19994657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9997323 + 9997324.

It is an arithmetic number, because the mean of its divisors is an integer number (9997324).

Almost surely, 2^19994647 is an apocalyptic number.

19994647 is a deficient number, since it is larger than the sum of its proper divisors (1).

19994647 is an equidigital number, since it uses as much as digits as its factorization.

19994647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 489888, while the sum is 49.

The square root of 19994647 is about 4471.5374313540. The cubic root of 19994647 is about 271.4175423694.

The spelling of 19994647 in words is "nineteen million, nine hundred ninety-four thousand, six hundred forty-seven".