19668457 has 2 divisors, whose sum is σ = 19668458. Its totient is φ = 19668456.

The previous prime is 19668449. The next prime is 19668487. The reversal of 19668457 is 75486691.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16556761 + 3111696 = 4069^2 + 1764^2 .

It is a cyclic number.

It is not a de Polignac number, because 19668457 - 2³ = 19668449 is a prime.

It is not a weakly prime, because it can be changed into another prime (19668487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9834228 + 9834229.

It is an arithmetic number, because the mean of its divisors is an integer number (9834229).

Almost surely, 2^19668457 is an apocalyptic number.

It is an amenable number.

19668457 is a deficient number, since it is larger than the sum of its proper divisors (1).

19668457 is an equidigital number, since it uses as much as digits as its factorization.

19668457 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 46.

The square root of 19668457 is about 4434.9134151638. The cubic root of 19668457 is about 269.9334861307.

The spelling of 19668457 in words is "nineteen million, six hundred sixty-eight thousand, four hundred fifty-seven".