16621513 has 2 divisors, whose sum is σ = 16621514. Its totient is φ = 16621512.

The previous prime is 16621511. The next prime is 16621541. The reversal of 16621513 is 31512661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14807104 + 1814409 = 3848^2 + 1347^2 .

It is a cyclic number.

It is not a de Polignac number, because 16621513 - 2¹ = 16621511 is a prime.

Together with 16621511, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (16621511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8310756 + 8310757.

It is an arithmetic number, because the mean of its divisors is an integer number (8310757).

Almost surely, 2^16621513 is an apocalyptic number.

It is an amenable number.

16621513 is a deficient number, since it is larger than the sum of its proper divisors (1).

16621513 is an equidigital number, since it uses as much as digits as its factorization.

16621513 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1080, while the sum is 25.

The square root of 16621513 is about 4076.9489817755. The cubic root of 16621513 is about 255.2055909602.

The spelling of 16621513 in words is "sixteen million, six hundred twenty-one thousand, five hundred thirteen".