21849523 has 2 divisors, whose sum is σ = 21849524. Its totient is φ = 21849522.

The previous prime is 21849521. The next prime is 21849551. The reversal of 21849523 is 32594812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21849523 - 2¹ = 21849521 is a prime.

Together with 21849521, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21849521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10924761 + 10924762.

It is an arithmetic number, because the mean of its divisors is an integer number (10924762).

Almost surely, 2^21849523 is an apocalyptic number.

21849523 is a deficient number, since it is larger than the sum of its proper divisors (1).

21849523 is an equidigital number, since it uses as much as digits as its factorization.

21849523 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 34.

The square root of 21849523 is about 4674.3473341206. The cubic root of 21849523 is about 279.5636187205.

The spelling of 21849523 in words is "twenty-one million, eight hundred forty-nine thousand, five hundred twenty-three".