21431324 has 6 divisors (see below), whose sum is σ = 37504824. Its totient is φ = 10715660.

The previous prime is 21431317. The next prime is 21431341. The reversal of 21431324 is 42313412.

It is a junction number, because it is equal to n+sod(n) for n = 21431296 and 21431305.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2678912 + ... + 2678919.

It is an arithmetic number, because the mean of its divisors is an integer number (6250804).

Almost surely, 2^21431324 is an apocalyptic number.

It is an amenable number.

21431324 is a deficient number, since it is larger than the sum of its proper divisors (16073500).

21431324 is a wasteful number, since it uses less digits than its factorization.

21431324 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5357835 (or 5357833 counting only the distinct ones).

The product of its digits is 576, while the sum is 20.

The square root of 21431324 is about 4629.3978010104. The cubic root of 21431324 is about 277.7685045556.

Adding to 21431324 its reverse (42313412), we get a palindrome (63744736).

The spelling of 21431324 in words is "twenty-one million, four hundred thirty-one thousand, three hundred twenty-four".