21759477877 has 2 divisors, whose sum is σ = 21759477878. Its totient is φ = 21759477876.

The previous prime is 21759477869. The next prime is 21759477907. The reversal of 21759477877 is 77877495712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16414990641 + 5344487236 = 128121^2 + 73106^2 .

It is a cyclic number.

It is not a de Polignac number, because 21759477877 - 2³ = 21759477869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21759447877) 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, 10879738938 + 10879738939.

It is an arithmetic number, because the mean of its divisors is an integer number (10879738939).

Almost surely, 2^21759477877 is an apocalyptic number.

It is an amenable number.

21759477877 is a deficient number, since it is larger than the sum of its proper divisors (1).

21759477877 is an equidigital number, since it uses as much as digits as its factorization.

21759477877 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48404160, while the sum is 64.

The spelling of 21759477877 in words is "twenty-one billion, seven hundred fifty-nine million, four hundred seventy-seven thousand, eight hundred seventy-seven".