16668749 has 2 divisors, whose sum is σ = 16668750. Its totient is φ = 16668748.

The previous prime is 16668733. The next prime is 16668791. The reversal of 16668749 is 94786661.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13032100 + 3636649 = 3610^2 + 1907^2 .

It is a cyclic number.

It is not a de Polignac number, because 16668749 - 2⁴ = 16668733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16668709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8334374 + 8334375.

It is an arithmetic number, because the mean of its divisors is an integer number (8334375).

Almost surely, 2^16668749 is an apocalyptic number.

It is an amenable number.

16668749 is a deficient number, since it is larger than the sum of its proper divisors (1).

16668749 is an equidigital number, since it uses as much as digits as its factorization.

16668749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 435456, while the sum is 47.

The square root of 16668749 is about 4082.7379293802. The cubic root of 16668749 is about 255.4471150993.

The spelling of 16668749 in words is "sixteen million, six hundred sixty-eight thousand, seven hundred forty-nine".