21221220221129 has 2 divisors, whose sum is σ = 21221220221130. Its totient is φ = 21221220221128.

The previous prime is 21221220221041. The next prime is 21221220221171. The reversal of 21221220221129 is 92112202212212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21023582181904 + 197638039225 = 4585148^2 + 444565^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221220221129 - 2¹² = 21221220217033 is a prime.

It is not a weakly prime, because it can be changed into another prime (21221220229129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610610110564 + 10610610110565.

It is an arithmetic number, because the mean of its divisors is an integer number (10610610110565).

Almost surely, 2^{21221220221129} is an apocalyptic number.

It is an amenable number.

21221220221129 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221220221129 is an equidigital number, since it uses as much as digits as its factorization.

21221220221129 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 29.

The spelling of 21221220221129 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twenty million, two hundred twenty-one thousand, one hundred twenty-nine".