16620391 has 2 divisors, whose sum is σ = 16620392. Its totient is φ = 16620390.

The previous prime is 16620361. The next prime is 16620431. The reversal of 16620391 is 19302661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 16620391 - 2⁹ = 16619879 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16620301) 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, 8310195 + 8310196.

It is an arithmetic number, because the mean of its divisors is an integer number (8310196).

Almost surely, 2^16620391 is an apocalyptic number.

16620391 is a deficient number, since it is larger than the sum of its proper divisors (1).

16620391 is an equidigital number, since it uses as much as digits as its factorization.

16620391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 16620391 is about 4076.8113765540. The cubic root of 16620391 is about 255.1998484602.

The spelling of 16620391 in words is "sixteen million, six hundred twenty thousand, three hundred ninety-one".