16616491 has 2 divisors, whose sum is σ = 16616492. Its totient is φ = 16616490.

The previous prime is 16616489. The next prime is 16616513. The reversal of 16616491 is 19461661.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (19461661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16616491 - 2¹ = 16616489 is a prime.

It is a super-2 number, since 2×16616491² = 552215546306162, which contains 22 as substring.

Together with 16616489, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (16610491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8308245 + 8308246.

It is an arithmetic number, because the mean of its divisors is an integer number (8308246).

Almost surely, 2^16616491 is an apocalyptic number.

16616491 is a deficient number, since it is larger than the sum of its proper divisors (1).

16616491 is an equidigital number, since it uses as much as digits as its factorization.

16616491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 34.

The square root of 16616491 is about 4076.3330334996. Note that the first 3 decimals coincide. The cubic root of 16616491 is about 255.1798858880.

The spelling of 16616491 in words is "sixteen million, six hundred sixteen thousand, four hundred ninety-one".