21210220221277 has 2 divisors, whose sum is σ = 21210220221278. Its totient is φ = 21210220221276.

The previous prime is 21210220221173. The next prime is 21210220221299. The reversal of 21210220221277 is 77212202201212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14105537878756 + 7104682342521 = 3755734^2 + 2665461^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210220221277 - 2¹⁹ = 21210219696989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21210220221877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605110110638 + 10605110110639.

It is an arithmetic number, because the mean of its divisors is an integer number (10605110110639).

Almost surely, 2^{21210220221277} is an apocalyptic number.

It is an amenable number.

21210220221277 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210220221277 is an equidigital number, since it uses as much as digits as its factorization.

21210220221277 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6272, while the sum is 31.

Adding to 21210220221277 its reverse (77212202201212), we get a palindrome (98422422422489).

The spelling of 21210220221277 in words is "twenty-one trillion, two hundred ten billion, two hundred twenty million, two hundred twenty-one thousand, two hundred seventy-seven".