16621749 has 6 divisors (see below), whose sum is σ = 24009206. Its totient is φ = 11081160.

The previous prime is 16621741. The next prime is 16621753. The reversal of 16621749 is 94712661.

It can be written as a sum of positive squares in only one way, i.e., 8820900 + 7800849 = 2970^2 + 2793^2 .

It is not a de Polignac number, because 16621749 - 2³ = 16621741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16621741) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 923422 + ... + 923439.

Almost surely, 2^16621749 is an apocalyptic number.

It is an amenable number.

16621749 is a deficient number, since it is larger than the sum of its proper divisors (7387457).

16621749 is a wasteful number, since it uses less digits than its factorization.

16621749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1846867 (or 1846864 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 16621749 is about 4076.9779248850. The cubic root of 16621749 is about 255.2067987972.

The spelling of 16621749 in words is "sixteen million, six hundred twenty-one thousand, seven hundred forty-nine".