21469849 has 2 divisors, whose sum is σ = 21469850. Its totient is φ = 21469848.

The previous prime is 21469843. The next prime is 21469853. The reversal of 21469849 is 94896412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17640000 + 3829849 = 4200^2 + 1957^2 .

It is a cyclic number.

It is not a de Polignac number, because 21469849 - 2¹⁷ = 21338777 is a prime.

It is not a weakly prime, because it can be changed into another prime (21469843) 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, 10734924 + 10734925.

It is an arithmetic number, because the mean of its divisors is an integer number (10734925).

Almost surely, 2^21469849 is an apocalyptic number.

It is an amenable number.

21469849 is a deficient number, since it is larger than the sum of its proper divisors (1).

21469849 is an equidigital number, since it uses as much as digits as its factorization.

21469849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 124416, while the sum is 43.

The square root of 21469849 is about 4633.5568411319. The cubic root of 21469849 is about 277.9348440371.

The spelling of 21469849 in words is "twenty-one million, four hundred sixty-nine thousand, eight hundred forty-nine".