16425221 has 2 divisors, whose sum is σ = 16425222. Its totient is φ = 16425220.

The previous prime is 16425203. The next prime is 16425229. The reversal of 16425221 is 12252461.

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., 14145121 + 2280100 = 3761^2 + 1510^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16425221 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16425229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8212610 + 8212611.

It is an arithmetic number, because the mean of its divisors is an integer number (8212611).

Almost surely, 2^16425221 is an apocalyptic number.

It is an amenable number.

16425221 is a deficient number, since it is larger than the sum of its proper divisors (1).

16425221 is an equidigital number, since it uses as much as digits as its factorization.

16425221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 960, while the sum is 23.

The square root of 16425221 is about 4052.8040909968. The cubic root of 16425221 is about 254.1969920757.

Adding to 16425221 its reverse (12252461), we get a palindrome (28677682).

The spelling of 16425221 in words is "sixteen million, four hundred twenty-five thousand, two hundred twenty-one".