16220621 has 2 divisors, whose sum is σ = 16220622. Its totient is φ = 16220620.

The previous prime is 16220609. The next prime is 16220629. The reversal of 16220621 is 12602261.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12460900 + 3759721 = 3530^2 + 1939^2 .

It is a cyclic number.

It is not a de Polignac number, because 16220621 - 2¹⁸ = 15958477 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 16220593 and 16220602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16220629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8110310 + 8110311.

It is an arithmetic number, because the mean of its divisors is an integer number (8110311).

Almost surely, 2^16220621 is an apocalyptic number.

It is an amenable number.

16220621 is a deficient number, since it is larger than the sum of its proper divisors (1).

16220621 is an equidigital number, since it uses as much as digits as its factorization.

16220621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 16220621 is about 4027.4832091518. The cubic root of 16220621 is about 253.1371147176.

Adding to 16220621 its reverse (12602261), we get a palindrome (28822882).

The spelling of 16220621 in words is "sixteen million, two hundred twenty thousand, six hundred twenty-one".