21425549 has 2 divisors, whose sum is σ = 21425550. Its totient is φ = 21425548.

The previous prime is 21425539. The next prime is 21425587. The reversal of 21425549 is 94552412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18003049 + 3422500 = 4243^2 + 1850^2 .

It is a cyclic number.

It is not a de Polignac number, because 21425549 - 2⁴ = 21425533 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21425539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10712774 + 10712775.

It is an arithmetic number, because the mean of its divisors is an integer number (10712775).

Almost surely, 2^21425549 is an apocalyptic number.

It is an amenable number.

21425549 is a deficient number, since it is larger than the sum of its proper divisors (1).

21425549 is an equidigital number, since it uses as much as digits as its factorization.

21425549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14400, while the sum is 32.

The square root of 21425549 is about 4628.7740277529. The cubic root of 21425549 is about 277.7435526485.

The spelling of 21425549 in words is "twenty-one million, four hundred twenty-five thousand, five hundred forty-nine".