21221201212061 has 2 divisors, whose sum is σ = 21221201212062. Its totient is φ = 21221201212060.

The previous prime is 21221201212027. The next prime is 21221201212109. The reversal of 21221201212061 is 16021210212212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20895595168900 + 325606043161 = 4571170^2 + 570619^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221201212061 - 2¹⁸ = 21221200949917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221201212361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610600606030 + 10610600606031.

It is an arithmetic number, because the mean of its divisors is an integer number (10610600606031).

Almost surely, 2^{21221201212061} is an apocalyptic number.

It is an amenable number.

21221201212061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221201212061 is an equidigital number, since it uses as much as digits as its factorization.

21221201212061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 23.

Adding to 21221201212061 its reverse (16021210212212), we get a palindrome (37242411424273).

The spelling of 21221201212061 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred one million, two hundred twelve thousand, sixty-one".