21533925 has 24 divisors (see below), whose sum is σ = 40689856. Its totient is φ = 9843840.

The previous prime is 21533923. The next prime is 21533929. The reversal of 21533925 is 52933512.

It is not a de Polignac number, because 21533925 - 2¹ = 21533923 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21533892 and 21533901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21533923) 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 23 ways as a sum of consecutive naturals, for example, 19984 + ... + 21033.

Almost surely, 2^21533925 is an apocalyptic number.

21533925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21533925 is a deficient number, since it is larger than the sum of its proper divisors (19155931).

21533925 is a wasteful number, since it uses less digits than its factorization.

21533925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41037 (or 41032 counting only the distinct ones).

The product of its digits is 8100, while the sum is 30.

The square root of 21533925 is about 4640.4660326308. The cubic root of 21533925 is about 278.2110649777.

The spelling of 21533925 in words is "twenty-one million, five hundred thirty-three thousand, nine hundred twenty-five".