16402121 has 2 divisors, whose sum is σ = 16402122. Its totient is φ = 16402120.

The previous prime is 16402079. The next prime is 16402129. The reversal of 16402121 is 12120461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15912121 + 490000 = 3989^2 + 700^2 .

It is a cyclic number.

It is not a de Polignac number, because 16402121 - 2¹⁰ = 16401097 is a prime.

It is a Chen prime.

It is a nialpdrome in base 8.

It is a self number, because there is not a number n which added to its sum of digits gives 16402121.

It is not a weakly prime, because it can be changed into another prime (16402129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8201060 + 8201061.

It is an arithmetic number, because the mean of its divisors is an integer number (8201061).

Almost surely, 2^16402121 is an apocalyptic number.

It is an amenable number.

16402121 is a deficient number, since it is larger than the sum of its proper divisors (1).

16402121 is an equidigital number, since it uses as much as digits as its factorization.

16402121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 16402121 is about 4049.9532096063. The cubic root of 16402121 is about 254.0777708409.

Adding to 16402121 its reverse (12120461), we get a palindrome (28522582).

The spelling of 16402121 in words is "sixteen million, four hundred two thousand, one hundred twenty-one".