21525157 has 16 divisors (see below), whose sum is σ = 23669440. Its totient is φ = 19502208.

The previous prime is 21525151. The next prime is 21525167. The reversal of 21525157 is 75152512.

It is a de Polignac number, because none of the positive numbers 2^k-21525157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21525151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46873 + ... + 47329.

It is an arithmetic number, because the mean of its divisors is an integer number (1479340).

Almost surely, 2^21525157 is an apocalyptic number.

It is an amenable number.

21525157 is a deficient number, since it is larger than the sum of its proper divisors (2144283).

21525157 is a wasteful number, since it uses less digits than its factorization.

21525157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 580.

The product of its digits is 3500, while the sum is 28.

The square root of 21525157 is about 4639.5212037451. The cubic root of 21525157 is about 278.1732999818.

Adding to 21525157 its reverse (75152512), we get a palindrome (96677669).

The spelling of 21525157 in words is "twenty-one million, five hundred twenty-five thousand, one hundred fifty-seven".