21533442 has 24 divisors (see below), whose sum is σ = 50098896. Its totient is φ = 6152328.

The previous prime is 21533431. The next prime is 21533443. The reversal of 21533442 is 24433512.

It is not an unprimeable number, because it can be changed into a prime (21533443) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 36328 + ... + 36915.

It is an arithmetic number, because the mean of its divisors is an integer number (2087454).

Almost surely, 2^21533442 is an apocalyptic number.

21533442 is an abundant number, since it is smaller than the sum of its proper divisors (28565454).

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

21533442 is a wasteful number, since it uses less digits than its factorization.

21533442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73262 (or 73255 counting only the distinct ones).

The product of its digits is 2880, while the sum is 24.

The square root of 21533442 is about 4640.4139901522. The cubic root of 21533442 is about 278.2089848963.

Adding to 21533442 its reverse (24433512), we get a palindrome (45966954).

The spelling of 21533442 in words is "twenty-one million, five hundred thirty-three thousand, four hundred forty-two".