21224131 has 2 divisors, whose sum is σ = 21224132. Its totient is φ = 21224130.

The previous prime is 21224123. The next prime is 21224141. The reversal of 21224131 is 13142212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21224131 - 2³ = 21224123 is a prime.

It is a super-2 number, since 2×21224131² = 900927473410322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21224141) 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 as a sum of consecutive naturals, namely, 10612065 + 10612066.

It is an arithmetic number, because the mean of its divisors is an integer number (10612066).

Almost surely, 2^21224131 is an apocalyptic number.

21224131 is a deficient number, since it is larger than the sum of its proper divisors (1).

21224131 is an equidigital number, since it uses as much as digits as its factorization.

21224131 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96, while the sum is 16.

The square root of 21224131 is about 4606.9654871727. The cubic root of 21224131 is about 276.8704707903.

Adding to 21224131 its reverse (13142212), we get a palindrome (34366343).

The spelling of 21224131 in words is "twenty-one million, two hundred twenty-four thousand, one hundred thirty-one".