21484409 has 2 divisors, whose sum is σ = 21484410. Its totient is φ = 21484408.

The previous prime is 21484403. The next prime is 21484453. The reversal of 21484409 is 90448412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17472400 + 4012009 = 4180^2 + 2003^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21484409 is a prime.

It is not a weakly prime, because it can be changed into another prime (21484403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10742204 + 10742205.

It is an arithmetic number, because the mean of its divisors is an integer number (10742205).

Almost surely, 2^21484409 is an apocalyptic number.

It is an amenable number.

21484409 is a deficient number, since it is larger than the sum of its proper divisors (1).

21484409 is an equidigital number, since it uses as much as digits as its factorization.

21484409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 21484409 is about 4635.1277220806. The cubic root of 21484409 is about 277.9976579690.

The spelling of 21484409 in words is "twenty-one million, four hundred eighty-four thousand, four hundred nine".