1211320221989 has 2 divisors, whose sum is σ = 1211320221990. Its totient is φ = 1211320221988.

The previous prime is 1211320221973. The next prime is 1211320222009. The reversal of 1211320221989 is 9891220231121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 980288109025 + 231032112964 = 990095^2 + 480658^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211320221989 - 2⁴ = 1211320221973 is a prime.

It is a super-2 number, since 2×1211320221989² (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 (1211320221959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605660110994 + 605660110995.

It is an arithmetic number, because the mean of its divisors is an integer number (605660110995).

Almost surely, 2^{1211320221989} is an apocalyptic number.

It is an amenable number.

1211320221989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211320221989 is an equidigital number, since it uses as much as digits as its factorization.

1211320221989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 41.

The spelling of 1211320221989 in words is "one trillion, two hundred eleven billion, three hundred twenty million, two hundred twenty-one thousand, nine hundred eighty-nine".