21050550361 has 2 divisors, whose sum is σ = 21050550362. Its totient is φ = 21050550360.

The previous prime is 21050550347. The next prime is 21050550413. The reversal of 21050550361 is 16305505012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21048206400 + 2343961 = 145080^2 + 1531^2 .

It is a cyclic number.

It is not a de Polignac number, because 21050550361 - 2¹⁷ = 21050419289 is a prime.

It is not a weakly prime, because it can be changed into another prime (21050550331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525275180 + 10525275181.

It is an arithmetic number, because the mean of its divisors is an integer number (10525275181).

Almost surely, 2^21050550361 is an apocalyptic number.

It is an amenable number.

21050550361 is a deficient number, since it is larger than the sum of its proper divisors (1).

21050550361 is an equidigital number, since it uses as much as digits as its factorization.

21050550361 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4500, while the sum is 28.

The spelling of 21050550361 in words is "twenty-one billion, fifty million, five hundred fifty thousand, three hundred sixty-one".