21504854377 has 2 divisors, whose sum is σ = 21504854378. Its totient is φ = 21504854376.

The previous prime is 21504854339. The next prime is 21504854443. The reversal of 21504854377 is 77345840512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12737153881 + 8767700496 = 112859^2 + 93636^2 .

It is a cyclic number.

It is not a de Polignac number, because 21504854377 - 2³¹ = 19357370729 is a prime.

It is not a weakly prime, because it can be changed into another prime (21504854317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10752427188 + 10752427189.

It is an arithmetic number, because the mean of its divisors is an integer number (10752427189).

Almost surely, 2^21504854377 is an apocalyptic number.

It is an amenable number.

21504854377 is a deficient number, since it is larger than the sum of its proper divisors (1).

21504854377 is an equidigital number, since it uses as much as digits as its factorization.

21504854377 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 940800, while the sum is 46.

The spelling of 21504854377 in words is "twenty-one billion, five hundred four million, eight hundred fifty-four thousand, three hundred seventy-seven".