21238529 has 8 divisors (see below), whose sum is σ = 23002560. Its totient is φ = 19493136.

The previous prime is 21238519. The next prime is 21238543. The reversal of 21238529 is 92583212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21238529 - 2⁴ = 21238513 is a prime.

It is a super-2 number, since 2×21238529² = 902150228167682, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21238495 and 21238504.

It is not an unprimeable number, because it can be changed into a prime (21238519) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2237 + ... + 6890.

It is an arithmetic number, because the mean of its divisors is an integer number (2875320).

Almost surely, 2^21238529 is an apocalyptic number.

It is an amenable number.

21238529 is a deficient number, since it is larger than the sum of its proper divisors (1764031).

21238529 is a wasteful number, since it uses less digits than its factorization.

21238529 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9319.

The product of its digits is 8640, while the sum is 32.

The square root of 21238529 is about 4608.5278560512. The cubic root of 21238529 is about 276.9330643221.

The spelling of 21238529 in words is "twenty-one million, two hundred thirty-eight thousand, five hundred twenty-nine".