21221111221061 has 2 divisors, whose sum is σ = 21221111221062. Its totient is φ = 21221111221060.

The previous prime is 21221111221043. The next prime is 21221111221069. The reversal of 21221111221061 is 16012211112212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19085146509025 + 2135964712036 = 4368655^2 + 1461494^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221111221061 - 2²⁶ = 21221044112197 is a prime.

It is a super-2 number, since 2×21221111221061² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221111221069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610555610530 + 10610555610531.

It is an arithmetic number, because the mean of its divisors is an integer number (10610555610531).

Almost surely, 2^{21221111221061} is an apocalyptic number.

It is an amenable number.

21221111221061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221111221061 is an equidigital number, since it uses as much as digits as its factorization.

21221111221061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 23.

Adding to 21221111221061 its reverse (16012211112212), we get a palindrome (37233322333273).

The spelling of 21221111221061 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred eleven million, two hundred twenty-one thousand, sixty-one".