21456349 has 2 divisors, whose sum is σ = 21456350. Its totient is φ = 21456348.

The previous prime is 21456341. The next prime is 21456373. The reversal of 21456349 is 94365412.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19740249 + 1716100 = 4443^2 + 1310^2 .

It is a cyclic number.

It is not a de Polignac number, because 21456349 - 2³ = 21456341 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21456341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10728174 + 10728175.

It is an arithmetic number, because the mean of its divisors is an integer number (10728175).

Almost surely, 2^21456349 is an apocalyptic number.

It is an amenable number.

21456349 is a deficient number, since it is larger than the sum of its proper divisors (1).

21456349 is an equidigital number, since it uses as much as digits as its factorization.

21456349 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25920, while the sum is 34.

The square root of 21456349 is about 4632.0998478012. The cubic root of 21456349 is about 277.8765777199.

The spelling of 21456349 in words is "twenty-one million, four hundred fifty-six thousand, three hundred forty-nine".