21142524 has 48 divisors (see below), whose sum is σ = 53420192. Its totient is φ = 6469632.

The previous prime is 21142493. The next prime is 21142529. The reversal of 21142524 is 42524112.

It is a self number, because there is not a number n which added to its sum of digits gives 21142524.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21142529) 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, 48612 + ... + 49044.

Almost surely, 2^21142524 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 21142524, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26710096).

21142524 is an abundant number, since it is smaller than the sum of its proper divisors (32277668).

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

21142524 is a wasteful number, since it uses less digits than its factorization.

21142524 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 766 (or 764 counting only the distinct ones).

The product of its digits is 640, while the sum is 21.

The square root of 21142524 is about 4598.1000424088. The cubic root of 21142524 is about 276.5151584132.

Adding to 21142524 its reverse (42524112), we get a palindrome (63666636).

The spelling of 21142524 in words is "twenty-one million, one hundred forty-two thousand, five hundred twenty-four".