16644557 has 2 divisors, whose sum is σ = 16644558. Its totient is φ = 16644556.

The previous prime is 16644553. The next prime is 16644577. The reversal of 16644557 is 75544661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9853321 + 6791236 = 3139^2 + 2606^2 .

It is a cyclic number.

It is not a de Polignac number, because 16644557 - 2² = 16644553 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 16644557.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16644553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8322278 + 8322279.

It is an arithmetic number, because the mean of its divisors is an integer number (8322279).

Almost surely, 2^16644557 is an apocalyptic number.

It is an amenable number.

16644557 is a deficient number, since it is larger than the sum of its proper divisors (1).

16644557 is an equidigital number, since it uses as much as digits as its factorization.

16644557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 100800, while the sum is 38.

The square root of 16644557 is about 4079.7741359051. The cubic root of 16644557 is about 255.3234751735.

The spelling of 16644557 in words is "sixteen million, six hundred forty-four thousand, five hundred fifty-seven".