21525124 has 6 divisors (see below), whose sum is σ = 37668974. Its totient is φ = 10762560.

The previous prime is 21525121. The next prime is 21525139. The reversal of 21525124 is 42152512.

It can be written as a sum of positive squares in only one way, i.e., 14137600 + 7387524 = 3760^2 + 2718^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21525095 and 21525104.

It is not an unprimeable number, because it can be changed into a prime (21525121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2690637 + ... + 2690644.

Almost surely, 2^21525124 is an apocalyptic number.

It is an amenable number.

21525124 is a deficient number, since it is larger than the sum of its proper divisors (16143850).

21525124 is a wasteful number, since it uses less digits than its factorization.

21525124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5381285 (or 5381283 counting only the distinct ones).

The product of its digits is 800, while the sum is 22.

The square root of 21525124 is about 4639.5176473422. The cubic root of 21525124 is about 278.1731578268.

Adding to 21525124 its reverse (42152512), we get a palindrome (63677636).

The spelling of 21525124 in words is "twenty-one million, five hundred twenty-five thousand, one hundred twenty-four".