21533031 has 12 divisors (see below), whose sum is σ = 33496008. Its totient is φ = 13251024.

The previous prime is 21533011. The next prime is 21533047. The reversal of 21533031 is 13033512.

It is not a de Polignac number, because 21533031 - 2⁶ = 21532967 is a prime.

It is a super-2 number, since 2×21533031² = 927342848093922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21532995 and 21533013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21533011) 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 11 ways as a sum of consecutive naturals, for example, 91905 + ... + 92138.

It is an arithmetic number, because the mean of its divisors is an integer number (2791334).

Almost surely, 2^21533031 is an apocalyptic number.

21533031 is a deficient number, since it is larger than the sum of its proper divisors (11962977).

21533031 is a wasteful number, since it uses less digits than its factorization.

21533031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184062 (or 184059 counting only the distinct ones).

The product of its (nonzero) digits is 270, while the sum is 18.

The square root of 21533031 is about 4640.3697050989. The cubic root of 21533031 is about 278.2072148647.

Adding to 21533031 its reverse (13033512), we get a palindrome (34566543).

It can be divided in two parts, 2153 and 3031, that added together give a square (5184 = 72²).

The spelling of 21533031 in words is "twenty-one million, five hundred thirty-three thousand, thirty-one".