1999772197 has 2 divisors, whose sum is σ = 1999772198. Its totient is φ = 1999772196.

The previous prime is 1999772179. The next prime is 1999772213. The reversal of 1999772197 is 7912779991.

Together with previous prime (1999772179) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1953109636 + 46662561 = 44194^2 + 6831^2 .

It is a cyclic number.

It is not a de Polignac number, because 1999772197 - 2¹⁵ = 1999739429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1999772597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999886098 + 999886099.

It is an arithmetic number, because the mean of its divisors is an integer number (999886099).

Almost surely, 2^1999772197 is an apocalyptic number.

It is an amenable number.

1999772197 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999772197 is an equidigital number, since it uses as much as digits as its factorization.

1999772197 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4500846, while the sum is 61.

The square root of 1999772197 is about 44718.8125624999. The cubic root of 1999772197 is about 1259.8732124461.

The spelling of 1999772197 in words is "one billion, nine hundred ninety-nine million, seven hundred seventy-two thousand, one hundred ninety-seven".