1021210121209 has 2 divisors, whose sum is σ = 1021210121210. Its totient is φ = 1021210121208.

The previous prime is 1021210121123. The next prime is 1021210121237. The reversal of 1021210121209 is 9021210121201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 553196787984 + 468013333225 = 743772^2 + 684115^2 .

It is an emirp because it is prime and its reverse (9021210121201) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1021210121209 - 2¹³ = 1021210113017 is a prime.

It is a super-2 number, since 2×1021210121209² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1021210121209.

It is not a weakly prime, because it can be changed into another prime (1021210121249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510605060604 + 510605060605.

It is an arithmetic number, because the mean of its divisors is an integer number (510605060605).

Almost surely, 2^{1021210121209} is an apocalyptic number.

It is an amenable number.

1021210121209 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021210121209 is an equidigital number, since it uses as much as digits as its factorization.

1021210121209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 22.

The spelling of 1021210121209 in words is "one trillion, twenty-one billion, two hundred ten million, one hundred twenty-one thousand, two hundred nine".