1221222100981 has 2 divisors, whose sum is σ = 1221222100982. Its totient is φ = 1221222100980.

The previous prime is 1221222100963. The next prime is 1221222101017. The reversal of 1221222100981 is 1890012221221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1025976539025 + 195245561956 = 1012905^2 + 441866^2 .

It is an emirp because it is prime and its reverse (1890012221221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221222100981 - 2²⁹ = 1220685230069 is a prime.

It is a super-2 number, since 2×1221222100981² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221222100921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610611050490 + 610611050491.

It is an arithmetic number, because the mean of its divisors is an integer number (610611050491).

Almost surely, 2^{1221222100981} is an apocalyptic number.

It is an amenable number.

1221222100981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221222100981 is an equidigital number, since it uses as much as digits as its factorization.

1221222100981 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 31.

The spelling of 1221222100981 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-two million, one hundred thousand, nine hundred eighty-one".