21264212777 has 2 divisors, whose sum is σ = 21264212778. Its totient is φ = 21264212776.

The previous prime is 21264212743. The next prime is 21264212807. The reversal of 21264212777 is 77721246212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20490204736 + 774008041 = 143144^2 + 27821^2 .

It is a cyclic number.

It is not a de Polignac number, because 21264212777 - 2²⁶ = 21197103913 is a prime.

It is not a weakly prime, because it can be changed into another prime (21264212737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10632106388 + 10632106389.

It is an arithmetic number, because the mean of its divisors is an integer number (10632106389).

Almost surely, 2^21264212777 is an apocalyptic number.

It is an amenable number.

21264212777 is a deficient number, since it is larger than the sum of its proper divisors (1).

21264212777 is an equidigital number, since it uses as much as digits as its factorization.

21264212777 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 131712, while the sum is 41.

Adding to 21264212777 its reverse (77721246212), we get a palindrome (98985458989).

The spelling of 21264212777 in words is "twenty-one billion, two hundred sixty-four million, two hundred twelve thousand, seven hundred seventy-seven".