21541533 has 16 divisors (see below), whose sum is σ = 32751936. Its totient is φ = 12476160.

The previous prime is 21541517. The next prime is 21541537. The reversal of 21541533 is 33514512.

It is not a de Polignac number, because 21541533 - 2⁴ = 21541517 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21541537) 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, 15583 + ... + 16908.

It is an arithmetic number, because the mean of its divisors is an integer number (2046996).

Almost surely, 2^21541533 is an apocalyptic number.

It is an amenable number.

21541533 is a deficient number, since it is larger than the sum of its proper divisors (11210403).

21541533 is a wasteful number, since it uses less digits than its factorization.

21541533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32524.

The product of its digits is 1800, while the sum is 24.

The square root of 21541533 is about 4641.2857054915. The cubic root of 21541533 is about 278.2438253865.

The spelling of 21541533 in words is "twenty-one million, five hundred forty-one thousand, five hundred thirty-three".