21353416 has 96 divisors (see below), whose sum is σ = 50889600. Its totient is φ = 8346240.

The previous prime is 21353401. The next prime is 21353417. The reversal of 21353416 is 61435312.

It is not an unprimeable number, because it can be changed into a prime (21353417) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 350026 + ... + 350086.

It is an arithmetic number, because the mean of its divisors is an integer number (530100).

Almost surely, 2^21353416 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21353416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25444800).

21353416 is an abundant number, since it is smaller than the sum of its proper divisors (29536184).

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

21353416 is a wasteful number, since it uses less digits than its factorization.

21353416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147 (or 136 counting only the distinct ones).

The product of its digits is 2160, while the sum is 25.

The square root of 21353416 is about 4620.9756545561. The cubic root of 21353416 is about 277.4315108417.

Adding to 21353416 its reverse (61435312), we get a palindrome (82788728).

The spelling of 21353416 in words is "twenty-one million, three hundred fifty-three thousand, four hundred sixteen".