21311124 has 12 divisors (see below), whose sum is σ = 49725984. Its totient is φ = 7103704.

The previous prime is 21311123. The next prime is 21311137. The reversal of 21311124 is 42111312.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×21311124² = 908328012286752, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311123) 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 3 ways as a sum of consecutive naturals, for example, 887952 + ... + 887975.

It is an arithmetic number, because the mean of its divisors is an integer number (4143832).

Almost surely, 2^21311124 is an apocalyptic number.

It is an amenable number.

21311124 is an abundant number, since it is smaller than the sum of its proper divisors (28414860).

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

21311124 is a wasteful number, since it uses less digits than its factorization.

21311124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1775934 (or 1775932 counting only the distinct ones).

The product of its digits is 48, while the sum is 15.

The square root of 21311124 is about 4616.3972965940. The cubic root of 21311124 is about 277.2482319992.

Adding to 21311124 its reverse (42111312), we get a palindrome (63422436).

The spelling of 21311124 in words is "twenty-one million, three hundred eleven thousand, one hundred twenty-four".