16620624221 has 2 divisors, whose sum is σ = 16620624222. Its totient is φ = 16620624220.

The previous prime is 16620624197. The next prime is 16620624269. The reversal of 16620624221 is 12242602661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8360359225 + 8260264996 = 91435^2 + 90886^2 .

It is a cyclic number.

It is not a de Polignac number, because 16620624221 - 2¹⁰ = 16620623197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16620624121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8310312110 + 8310312111.

It is an arithmetic number, because the mean of its divisors is an integer number (8310312111).

Almost surely, 2^16620624221 is an apocalyptic number.

It is an amenable number.

16620624221 is a deficient number, since it is larger than the sum of its proper divisors (1).

16620624221 is an equidigital number, since it uses as much as digits as its factorization.

16620624221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 32.

The spelling of 16620624221 in words is "sixteen billion, six hundred twenty million, six hundred twenty-four thousand, two hundred twenty-one".