21111344851 has 2 divisors, whose sum is σ = 21111344852. Its totient is φ = 21111344850.

The previous prime is 21111344843. The next prime is 21111344869. The reversal of 21111344851 is 15844311112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21111344851 - 2³ = 21111344843 is a prime.

It is not a weakly prime, because it can be changed into another prime (21111342851) 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, 10555672425 + 10555672426.

It is an arithmetic number, because the mean of its divisors is an integer number (10555672426).

Almost surely, 2^21111344851 is an apocalyptic number.

21111344851 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111344851 is an equidigital number, since it uses as much as digits as its factorization.

21111344851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3840, while the sum is 31.

Adding to 21111344851 its reverse (15844311112), we get a palindrome (36955655963).

The spelling of 21111344851 in words is "twenty-one billion, one hundred eleven million, three hundred forty-four thousand, eight hundred fifty-one".