21004424131 has 2 divisors, whose sum is σ = 21004424132. Its totient is φ = 21004424130.

The previous prime is 21004424087. The next prime is 21004424179. The reversal of 21004424131 is 13142440012.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21004424131 - 2²³ = 20996035523 is a prime.

It is a super-2 number, since 2×21004424131² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21004424191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10502212065 + 10502212066.

It is an arithmetic number, because the mean of its divisors is an integer number (10502212066).

Almost surely, 2^21004424131 is an apocalyptic number.

21004424131 is a deficient number, since it is larger than the sum of its proper divisors (1).

21004424131 is an equidigital number, since it uses as much as digits as its factorization.

21004424131 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 22.

Adding to 21004424131 its reverse (13142440012), we get a palindrome (34146864143).

The spelling of 21004424131 in words is "twenty-one billion, four million, four hundred twenty-four thousand, one hundred thirty-one".