21444330431 has 2 divisors, whose sum is σ = 21444330432. Its totient is φ = 21444330430.

The previous prime is 21444330359. The next prime is 21444330521. The reversal of 21444330431 is 13403344412.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21444330431 - 2¹⁰ = 21444329407 is a prime.

It is a super-2 number, since 2×21444330431² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21444330394 and 21444330403.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21444338431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10722165215 + 10722165216.

It is an arithmetic number, because the mean of its divisors is an integer number (10722165216).

Almost surely, 2^21444330431 is an apocalyptic number.

21444330431 is a deficient number, since it is larger than the sum of its proper divisors (1).

21444330431 is an equidigital number, since it uses as much as digits as its factorization.

21444330431 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 29.

Adding to 21444330431 its reverse (13403344412), we get a palindrome (34847674843).

The spelling of 21444330431 in words is "twenty-one billion, four hundred forty-four million, three hundred thirty thousand, four hundred thirty-one".