1691120001209 has 2 divisors, whose sum is σ = 1691120001210. Its totient is φ = 1691120001208.

The previous prime is 1691120001143. The next prime is 1691120001299. The reversal of 1691120001209 is 9021000211961.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1591816235584 + 99303765625 = 1261672^2 + 315125^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1691120001209 is a prime.

It is a super-2 number, since 2×1691120001209² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1691120001299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 845560000604 + 845560000605.

It is an arithmetic number, because the mean of its divisors is an integer number (845560000605).

Almost surely, 2^{1691120001209} is an apocalyptic number.

It is an amenable number.

1691120001209 is a deficient number, since it is larger than the sum of its proper divisors (1).

1691120001209 is an equidigital number, since it uses as much as digits as its factorization.

1691120001209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 32.

The spelling of 1691120001209 in words is "one trillion, six hundred ninety-one billion, one hundred twenty million, one thousand, two hundred nine".