21467909 has 2 divisors, whose sum is σ = 21467910. Its totient is φ = 21467908.

The previous prime is 21467899. The next prime is 21467933. The reversal of 21467909 is 90976412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21390625 + 77284 = 4625^2 + 278^2 .

It is a cyclic number.

It is not a de Polignac number, because 21467909 - 2⁴ = 21467893 is a prime.

It is a super-2 number, since 2×21467909² = 921742233664562, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21467959) 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, 10733954 + 10733955.

It is an arithmetic number, because the mean of its divisors is an integer number (10733955).

Almost surely, 2^21467909 is an apocalyptic number.

It is an amenable number.

21467909 is a deficient number, since it is larger than the sum of its proper divisors (1).

21467909 is an equidigital number, since it uses as much as digits as its factorization.

21467909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27216, while the sum is 38.

The square root of 21467909 is about 4633.3474939832. The cubic root of 21467909 is about 277.9264724546.

The spelling of 21467909 in words is "twenty-one million, four hundred sixty-seven thousand, nine hundred nine".