21331124 has 36 divisors (see below), whose sum is σ = 41045004. Its totient is φ = 9666048.

The previous prime is 21331109. The next prime is 21331127. The reversal of 21331124 is 42113312.

It can be written as a sum of positive squares in 6 ways, for example, as 792100 + 20539024 = 890^2 + 4532^2 .

It is a super-2 number, since 2×21331124² = 910033702206752, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331127) 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 11 ways as a sum of consecutive naturals, for example, 57002 + ... + 57374.

It is an arithmetic number, because the mean of its divisors is an integer number (1140139).

Almost surely, 2^21331124 is an apocalyptic number.

It is an amenable number.

21331124 is a deficient number, since it is larger than the sum of its proper divisors (19713880).

21331124 is a wasteful number, since it uses less digits than its factorization.

21331124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 452 (or 421 counting only the distinct ones).

The product of its digits is 144, while the sum is 17.

The square root of 21331124 is about 4618.5629799755. The cubic root of 21331124 is about 277.3349352461.

Adding to 21331124 its reverse (42113312), we get a palindrome (63444436).

The spelling of 21331124 in words is "twenty-one million, three hundred thirty-one thousand, one hundred twenty-four".