21520332 has 36 divisors (see below), whose sum is σ = 55429920. Its totient is φ = 7037472.

The previous prime is 21520307. The next prime is 21520361. The reversal of 21520332 is 23302512.

It is a tau number, because it is divible by the number of its divisors (36).

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3732 + ... + 7547.

It is an arithmetic number, because the mean of its divisors is an integer number (1539720).

Almost surely, 2^21520332 is an apocalyptic number.

It is an amenable number.

21520332 is an abundant number, since it is smaller than the sum of its proper divisors (33909588).

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

21520332 is a wasteful number, since it uses less digits than its factorization.

21520332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11342 (or 11337 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

The square root of 21520332 is about 4639.0011856002. The cubic root of 21520332 is about 278.1525136607.

Adding to 21520332 its reverse (23302512), we get a palindrome (44822844).

The spelling of 21520332 in words is "twenty-one million, five hundred twenty thousand, three hundred thirty-two".