21144545077 has 2 divisors, whose sum is σ = 21144545078. Its totient is φ = 21144545076.

The previous prime is 21144545063. The next prime is 21144545083. The reversal of 21144545077 is 77054544112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21071715921 + 72829156 = 145161^2 + 8534^2 .

It is a cyclic number.

It is not a de Polignac number, because 21144545077 - 2³¹ = 18997061429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21144545017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10572272538 + 10572272539.

It is an arithmetic number, because the mean of its divisors is an integer number (10572272539).

Almost surely, 2^21144545077 is an apocalyptic number.

It is an amenable number.

21144545077 is a deficient number, since it is larger than the sum of its proper divisors (1).

21144545077 is an equidigital number, since it uses as much as digits as its factorization.

21144545077 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 156800, while the sum is 40.

The spelling of 21144545077 in words is "twenty-one billion, one hundred forty-four million, five hundred forty-five thousand, seventy-seven".