21221976446777 has 2 divisors, whose sum is σ = 21221976446778. Its totient is φ = 21221976446776.

The previous prime is 21221976446771. The next prime is 21221976446813. The reversal of 21221976446777 is 77764467912212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11806535812096 + 9415440634681 = 3436064^2 + 3068459^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221976446777 - 2⁴ = 21221976446761 is a prime.

It is not a weakly prime, because it can be changed into another prime (21221976446771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610988223388 + 10610988223389.

It is an arithmetic number, because the mean of its divisors is an integer number (10610988223389).

Almost surely, 2^{21221976446777} is an apocalyptic number.

It is an amenable number.

21221976446777 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221976446777 is an equidigital number, since it uses as much as digits as its factorization.

21221976446777 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 99574272, while the sum is 65.

The spelling of 21221976446777 in words is "twenty-one trillion, two hundred twenty-one billion, nine hundred seventy-six million, four hundred forty-six thousand, seven hundred seventy-seven".