21464309 has 2 divisors, whose sum is σ = 21464310. Its totient is φ = 21464308.

The previous prime is 21464299. The next prime is 21464323. The reversal of 21464309 is 90346412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12180100 + 9284209 = 3490^2 + 3047^2 .

It is a cyclic number.

It is not a de Polignac number, because 21464309 - 2⁴ = 21464293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21467309) 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, 10732154 + 10732155.

It is an arithmetic number, because the mean of its divisors is an integer number (10732155).

Almost surely, 2^21464309 is an apocalyptic number.

It is an amenable number.

21464309 is a deficient number, since it is larger than the sum of its proper divisors (1).

21464309 is an equidigital number, since it uses as much as digits as its factorization.

21464309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 21464309 is about 4632.9589896739. The cubic root of 21464309 is about 277.9109362228.

The spelling of 21464309 in words is "twenty-one million, four hundred sixty-four thousand, three hundred nine".