21878280401 has 2 divisors, whose sum is σ = 21878280402. Its totient is φ = 21878280400.

The previous prime is 21878280353. The next prime is 21878280469. The reversal of 21878280401 is 10408287812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18982226176 + 2896054225 = 137776^2 + 53815^2 .

It is a cyclic number.

It is not a de Polignac number, because 21878280401 - 2¹⁰ = 21878279377 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21878280481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10939140200 + 10939140201.

It is an arithmetic number, because the mean of its divisors is an integer number (10939140201).

Almost surely, 2^21878280401 is an apocalyptic number.

It is an amenable number.

21878280401 is a deficient number, since it is larger than the sum of its proper divisors (1).

21878280401 is an equidigital number, since it uses as much as digits as its factorization.

21878280401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 57344, while the sum is 41.

The spelling of 21878280401 in words is "twenty-one billion, eight hundred seventy-eight million, two hundred eighty thousand, four hundred one".