1217108021 has 2 divisors, whose sum is σ = 1217108022. Its totient is φ = 1217108020.

The previous prime is 1217108017. The next prime is 1217108027. The reversal of 1217108021 is 1208017121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 812535025 + 404572996 = 28505^2 + 20114^2 .

It is a cyclic number.

It is not a de Polignac number, because 1217108021 - 2² = 1217108017 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1217108027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608554010 + 608554011.

It is an arithmetic number, because the mean of its divisors is an integer number (608554011).

Almost surely, 2^1217108021 is an apocalyptic number.

It is an amenable number.

1217108021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1217108021 is an equidigital number, since it uses as much as digits as its factorization.

1217108021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 224, while the sum is 23.

The square root of 1217108021 is about 34887.0752715099. The cubic root of 1217108021 is about 1067.6847546077.

The spelling of 1217108021 in words is "one billion, two hundred seventeen million, one hundred eight thousand, twenty-one".