1999772028109 has 2 divisors, whose sum is σ = 1999772028110. Its totient is φ = 1999772028108.

The previous prime is 1999772028041. The next prime is 1999772028157. The reversal of 1999772028109 is 9018202779991.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1079774530884 + 919997497225 = 1039122^2 + 959165^2 .

It is a cyclic number.

It is not a de Polignac number, because 1999772028109 - 2⁹ = 1999772027597 is a prime.

It is a super-2 number, since 2×1999772028109² (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 (1999772028169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999886014054 + 999886014055.

It is an arithmetic number, because the mean of its divisors is an integer number (999886014055).

Almost surely, 2^{1999772028109} is an apocalyptic number.

It is an amenable number.

1999772028109 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999772028109 is an equidigital number, since it uses as much as digits as its factorization.

1999772028109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10287648, while the sum is 64.

The spelling of 1999772028109 in words is "one trillion, nine hundred ninety-nine billion, seven hundred seventy-two million, twenty-eight thousand, one hundred nine".