16668647 has 2 divisors, whose sum is σ = 16668648. Its totient is φ = 16668646.

The previous prime is 16668569. The next prime is 16668683. The reversal of 16668647 is 74686661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 16668647 - 2¹² = 16664551 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 16668598 and 16668607.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16668697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8334323 + 8334324.

It is an arithmetic number, because the mean of its divisors is an integer number (8334324).

Almost surely, 2^16668647 is an apocalyptic number.

16668647 is a deficient number, since it is larger than the sum of its proper divisors (1).

16668647 is an equidigital number, since it uses as much as digits as its factorization.

16668647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 290304, while the sum is 44.

The square root of 16668647 is about 4082.7254377438. The cubic root of 16668647 is about 255.4465940513.

The spelling of 16668647 in words is "sixteen million, six hundred sixty-eight thousand, six hundred forty-seven".