21269449 has 2 divisors, whose sum is σ = 21269450. Its totient is φ = 21269448.

The previous prime is 21269401. The next prime is 21269467. The reversal of 21269449 is 94496212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15054400 + 6215049 = 3880^2 + 2493^2 .

It is a cyclic number.

It is not a de Polignac number, because 21269449 - 2⁷ = 21269321 is a prime.

It is not a weakly prime, because it can be changed into another prime (21269849) 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, 10634724 + 10634725.

It is an arithmetic number, because the mean of its divisors is an integer number (10634725).

Almost surely, 2^21269449 is an apocalyptic number.

It is an amenable number.

21269449 is a deficient number, since it is larger than the sum of its proper divisors (1).

21269449 is an equidigital number, since it uses as much as digits as its factorization.

21269449 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 37.

The square root of 21269449 is about 4611.8812864166. The cubic root of 21269449 is about 277.0673896693.

It can be divided in two parts, 2126944 and 9, that added together give a triangular number (2126953 = T₂₀₆₂).

The spelling of 21269449 in words is "twenty-one million, two hundred sixty-nine thousand, four hundred forty-nine".