21221487743 has 2 divisors, whose sum is σ = 21221487744. Its totient is φ = 21221487742.

The previous prime is 21221487739. The next prime is 21221487757. The reversal of 21221487743 is 34778412212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21221487743 - 2² = 21221487739 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21221487743.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221487043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610743871 + 10610743872.

It is an arithmetic number, because the mean of its divisors is an integer number (10610743872).

Almost surely, 2^21221487743 is an apocalyptic number.

21221487743 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221487743 is an equidigital number, since it uses as much as digits as its factorization.

21221487743 is an evil number, because the sum of its binary digits is even.

The product of its digits is 150528, while the sum is 41.

Adding to 21221487743 its reverse (34778412212), we get a palindrome (55999899955).

The spelling of 21221487743 in words is "twenty-one billion, two hundred twenty-one million, four hundred eighty-seven thousand, seven hundred forty-three".