21831528 has 32 divisors (see below), whose sum is σ = 54698400. Its totient is φ = 7261248.

The previous prime is 21831527. The next prime is 21831539. The reversal of 21831528 is 82513812.

It is a super-2 number, since 2×21831528² = 953231229629568, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21831495 and 21831504.

It is not an unprimeable number, because it can be changed into a prime (21831521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16375 + ... + 17657.

It is an arithmetic number, because the mean of its divisors is an integer number (1709325).

Almost surely, 2^21831528 is an apocalyptic number.

It is an amenable number.

21831528 is an abundant number, since it is smaller than the sum of its proper divisors (32866872).

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

21831528 is a wasteful number, since it uses less digits than its factorization.

21831528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2001 (or 1997 counting only the distinct ones).

The product of its digits is 3840, while the sum is 30.

The square root of 21831528 is about 4672.4220699761. The cubic root of 21831528 is about 279.4868492484.

The spelling of 21831528 in words is "twenty-one million, eight hundred thirty-one thousand, five hundred twenty-eight".