21251051443 has 2 divisors, whose sum is σ = 21251051444. Its totient is φ = 21251051442.

The previous prime is 21251051431. The next prime is 21251051453. The reversal of 21251051443 is 34415015212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21251051443 - 2¹³ = 21251043251 is a prime.

It is not a weakly prime, because it can be changed into another prime (21251051453) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10625525721 + 10625525722.

It is an arithmetic number, because the mean of its divisors is an integer number (10625525722).

Almost surely, 2^21251051443 is an apocalyptic number.

21251051443 is a deficient number, since it is larger than the sum of its proper divisors (1).

21251051443 is an equidigital number, since it uses as much as digits as its factorization.

21251051443 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4800, while the sum is 28.

Adding to 21251051443 its reverse (34415015212), we get a palindrome (55666066655).

The spelling of 21251051443 in words is "twenty-one billion, two hundred fifty-one million, fifty-one thousand, four hundred forty-three".