21545052 has 24 divisors (see below), whose sum is σ = 53229456. Its totient is φ = 6759168.

The previous prime is 21545047. The next prime is 21545059. The reversal of 21545052 is 25054512.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21545059) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52603 + ... + 53010.

It is an arithmetic number, because the mean of its divisors is an integer number (2217894).

Almost surely, 2^21545052 is an apocalyptic number.

It is an amenable number.

21545052 is an abundant number, since it is smaller than the sum of its proper divisors (31684404).

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

21545052 is a wasteful number, since it uses less digits than its factorization.

21545052 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105637 (or 105635 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 24.

The square root of 21545052 is about 4641.6647875520. The cubic root of 21545052 is about 278.2589757585.

Adding to 21545052 its reverse (25054512), we get a palindrome (46599564).

The spelling of 21545052 in words is "twenty-one million, five hundred forty-five thousand, fifty-two".