21453524 has 12 divisors (see below), whose sum is σ = 39752244. Its totient is φ = 10095744.

The previous prime is 21453493. The next prime is 21453529. The reversal of 21453524 is 42535412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 9412624 + 12040900 = 3068^2 + 3470^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21453493 and 21453502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21453529) 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 3 ways as a sum of consecutive naturals, for example, 157679 + ... + 157814.

It is an arithmetic number, because the mean of its divisors is an integer number (3312687).

Almost surely, 2^21453524 is an apocalyptic number.

It is an amenable number.

21453524 is a deficient number, since it is larger than the sum of its proper divisors (18298720).

21453524 is a wasteful number, since it uses less digits than its factorization.

21453524 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315514 (or 315512 counting only the distinct ones).

The product of its digits is 4800, while the sum is 26.

The square root of 21453524 is about 4631.7949004679. The cubic root of 21453524 is about 277.8643818614.

Adding to 21453524 its reverse (42535412), we get a palindrome (63988936).

The spelling of 21453524 in words is "twenty-one million, four hundred fifty-three thousand, five hundred twenty-four".