16638749 has 2 divisors, whose sum is σ = 16638750. Its totient is φ = 16638748.

The previous prime is 16638731. The next prime is 16638751. The reversal of 16638749 is 94783661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16605625 + 33124 = 4075^2 + 182^2 .

It is a cyclic number.

It is not a de Polignac number, because 16638749 - 2¹⁶ = 16573213 is a prime.

Together with 16638751, 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 (16638719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8319374 + 8319375.

It is an arithmetic number, because the mean of its divisors is an integer number (8319375).

Almost surely, 2^16638749 is an apocalyptic number.

It is an amenable number.

16638749 is a deficient number, since it is larger than the sum of its proper divisors (1).

16638749 is an equidigital number, since it uses as much as digits as its factorization.

16638749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 44.

The square root of 16638749 is about 4079.0622696890. The cubic root of 16638749 is about 255.2937739472.

The spelling of 16638749 in words is "sixteen million, six hundred thirty-eight thousand, seven hundred forty-nine".