21344531 has 12 divisors (see below), whose sum is σ = 23558688. Its totient is φ = 19322784.

The previous prime is 21344513. The next prime is 21344593. The reversal of 21344531 is 13544312.

It is not a de Polignac number, because 21344531 - 2²² = 17150227 is a prime.

It is a super-2 number, since 2×21344531² = 911178007219922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21344497 and 21344506.

It is not an unprimeable number, because it can be changed into a prime (21344131) 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, 7766 + ... + 10148.

It is an arithmetic number, because the mean of its divisors is an integer number (1963224).

Almost surely, 2^21344531 is an apocalyptic number.

21344531 is a deficient number, since it is larger than the sum of its proper divisors (2214157).

21344531 is a wasteful number, since it uses less digits than its factorization.

21344531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2462 (or 2449 counting only the distinct ones).

The product of its digits is 1440, while the sum is 23.

The square root of 21344531 is about 4620.0141774674. The cubic root of 21344531 is about 277.3930264303.

Adding to 21344531 its reverse (13544312), we get a palindrome (34888843).

It can be divided in two parts, 213 and 44531, that added together give a palindrome (44744).

The spelling of 21344531 in words is "twenty-one million, three hundred forty-four thousand, five hundred thirty-one".