21051324 has 36 divisors (see below), whose sum is σ = 60815664. Its totient is φ = 6014592.

The previous prime is 21051323. The next prime is 21051337. The reversal of 21051324 is 42315012.

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 a junction number, because it is equal to n+sod(n) for n = 21051297 and 21051306.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21051323) by changing a digit.

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, 41517 + ... + 42020.

It is an arithmetic number, because the mean of its divisors is an integer number (1689324).

Almost surely, 2^21051324 is an apocalyptic number.

It is an amenable number.

21051324 is an abundant number, since it is smaller than the sum of its proper divisors (39764340).

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

21051324 is a wasteful number, since it uses less digits than its factorization.

21051324 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83554 (or 83549 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21051324 is about 4588.1721850863. The cubic root of 21051324 is about 276.1169951378.

Adding to 21051324 its reverse (42315012), we get a palindrome (63366336).

The spelling of 21051324 in words is "twenty-one million, fifty-one thousand, three hundred twenty-four".