21849551 has 2 divisors, whose sum is σ = 21849552. Its totient is φ = 21849550.

The previous prime is 21849523. The next prime is 21849559. The reversal of 21849551 is 15594812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21849551 - 2¹⁰ = 21848527 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 (21849559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10924775 + 10924776.

It is an arithmetic number, because the mean of its divisors is an integer number (10924776).

Almost surely, 2^21849551 is an apocalyptic number.

21849551 is a deficient number, since it is larger than the sum of its proper divisors (1).

21849551 is an equidigital number, since it uses as much as digits as its factorization.

21849551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14400, while the sum is 35.

The square root of 21849551 is about 4674.3503291901. The cubic root of 21849551 is about 279.5637381400.

The spelling of 21849551 in words is "twenty-one million, eight hundred forty-nine thousand, five hundred fifty-one".