21131529 has 16 divisors (see below), whose sum is σ = 29183232. Its totient is φ = 13592448.

The previous prime is 21131519. The next prime is 21131531. The reversal of 21131529 is 92513112.

It is not a de Polignac number, because 21131529 - 2¹¹ = 21129481 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21131499 and 21131508.

It is not an unprimeable number, because it can be changed into a prime (21131519) 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, 9267 + ... + 11319.

It is an arithmetic number, because the mean of its divisors is an integer number (1823952).

Almost surely, 2^21131529 is an apocalyptic number.

It is an amenable number.

21131529 is a deficient number, since it is larger than the sum of its proper divisors (8051703).

21131529 is a wasteful number, since it uses less digits than its factorization.

21131529 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2176.

The product of its digits is 540, while the sum is 24.

The square root of 21131529 is about 4596.9042844071. The cubic root of 21131529 is about 276.4672169384.

The spelling of 21131529 in words is "twenty-one million, one hundred thirty-one thousand, five hundred twenty-nine".