21604050 has 96 divisors (see below), whose sum is σ = 64162560. Its totient is φ = 5313600.

The previous prime is 21604031. The next prime is 21604057. The reversal of 21604050 is 5040612.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21604057) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 16935 + ... + 18165.

It is an arithmetic number, because the mean of its divisors is an integer number (668360).

Almost surely, 2^21604050 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21604050, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32081280).

21604050 is an abundant number, since it is smaller than the sum of its proper divisors (42558510).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21604050 is a wasteful number, since it uses less digits than its factorization.

21604050 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1265 (or 1254 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21604050 is about 4648.0157056533. The cubic root of 21604050 is about 278.5127348871.

Adding to 21604050 its reverse (5040612), we get a palindrome (26644662).

The spelling of 21604050 in words is "twenty-one million, six hundred four thousand, fifty".