21109152 has 96 divisors (see below), whose sum is σ = 59512320. Its totient is φ = 6531840.

The previous prime is 21109139. The next prime is 21109159. The reversal of 21109152 is 25190112.

It is a tau number, because it is divible by the number of its divisors (96).

It is not an unprimeable number, because it can be changed into a prime (21109159) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 129423 + ... + 129585.

It is an arithmetic number, because the mean of its divisors is an integer number (619920).

Almost surely, 2^21109152 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 21109152, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29756160).

21109152 is an abundant number, since it is smaller than the sum of its proper divisors (38403168).

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

21109152 is a wasteful number, since it uses less digits than its factorization.

21109152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266 (or 258 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 21.

The square root of 21109152 is about 4594.4697191297. The cubic root of 21109152 is about 276.3695951666.

Adding to 21109152 its reverse (25190112), we get a palindrome (46299264).

The spelling of 21109152 in words is "twenty-one million, one hundred nine thousand, one hundred fifty-two".