21828349 has 2 divisors, whose sum is σ = 21828350. Its totient is φ = 21828348.

The previous prime is 21828341. The next prime is 21828353. The reversal of 21828349 is 94382812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17388900 + 4439449 = 4170^2 + 2107^2 .

It is a cyclic number.

It is not a de Polignac number, because 21828349 - 2³ = 21828341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21828341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10914174 + 10914175.

It is an arithmetic number, because the mean of its divisors is an integer number (10914175).

Almost surely, 2^21828349 is an apocalyptic number.

It is an amenable number.

21828349 is a deficient number, since it is larger than the sum of its proper divisors (1).

21828349 is an equidigital number, since it uses as much as digits as its factorization.

21828349 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27648, while the sum is 37.

The square root of 21828349 is about 4672.0818700019. The cubic root of 21828349 is about 279.4732827553.

The spelling of 21828349 in words is "twenty-one million, eight hundred twenty-eight thousand, three hundred forty-nine".