16662409 has 2 divisors, whose sum is σ = 16662410. Its totient is φ = 16662408.

The previous prime is 16662403. The next prime is 16662427. The reversal of 16662409 is 90426661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16581184 + 81225 = 4072^2 + 285^2 .

It is a cyclic number.

It is not a de Polignac number, because 16662409 - 2¹³ = 16654217 is a prime.

It is not a weakly prime, because it can be changed into another prime (16662403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8331204 + 8331205.

It is an arithmetic number, because the mean of its divisors is an integer number (8331205).

Almost surely, 2^16662409 is an apocalyptic number.

It is an amenable number.

16662409 is a deficient number, since it is larger than the sum of its proper divisors (1).

16662409 is an equidigital number, since it uses as much as digits as its factorization.

16662409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 16662409 is about 4081.9614157902. The cubic root of 16662409 is about 255.4147243446.

It can be divided in two parts, 16662 and 409, that added together give a palindrome (17071).

The spelling of 16662409 in words is "sixteen million, six hundred sixty-two thousand, four hundred nine".