21523849 has 8 divisors (see below), whose sum is σ = 22140000. Its totient is φ = 20916192.

The previous prime is 21523847. The next prime is 21523891. The reversal of 21523849 is 94832512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21523849 - 2¹ = 21523847 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21523847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3202 + ... + 7300.

It is an arithmetic number, because the mean of its divisors is an integer number (2767500).

Almost surely, 2^21523849 is an apocalyptic number.

It is an amenable number.

21523849 is a deficient number, since it is larger than the sum of its proper divisors (616151).

21523849 is an equidigital number, since it uses as much as digits as its factorization.

21523849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4247.

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

The square root of 21523849 is about 4639.3802387819. The cubic root of 21523849 is about 278.1676653648.

The spelling of 21523849 in words is "twenty-one million, five hundred twenty-three thousand, eight hundred forty-nine".