21189849 has 8 divisors (see below), whose sum is σ = 28274400. Its totient is φ = 14115936.

The previous prime is 21189827. The next prime is 21189899. The reversal of 21189849 is 94898112.

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

It is not a de Polignac number, because 21189849 - 2⁸ = 21189593 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21189849.

It is not an unprimeable number, because it can be changed into a prime (21189899) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6502 + ... + 9200.

It is an arithmetic number, because the mean of its divisors is an integer number (3534300).

Almost surely, 2^21189849 is an apocalyptic number.

It is an amenable number.

21189849 is a deficient number, since it is larger than the sum of its proper divisors (7084551).

21189849 is a wasteful number, since it uses less digits than its factorization.

21189849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5319.

The product of its digits is 41472, while the sum is 42.

The square root of 21189849 is about 4603.2433131435. The cubic root of 21189849 is about 276.7213199879.

The spelling of 21189849 in words is "twenty-one million, one hundred eighty-nine thousand, eight hundred forty-nine".