1909777997 has 2 divisors, whose sum is σ = 1909777998. Its totient is φ = 1909777996.

The previous prime is 1909777981. The next prime is 1909778009. The reversal of 1909777997 is 7997779091.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1713049321 + 196728676 = 41389^2 + 14026^2 .

It is a cyclic number.

It is not a de Polignac number, because 1909777997 - 2⁴ = 1909777981 is a prime.

It is a super-3 number, since 3×1909777997³ (a number of 29 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1909777957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 954888998 + 954888999.

It is an arithmetic number, because the mean of its divisors is an integer number (954888999).

Almost surely, 2^1909777997 is an apocalyptic number.

It is an amenable number.

1909777997 is a deficient number, since it is larger than the sum of its proper divisors (1).

1909777997 is an equidigital number, since it uses as much as digits as its factorization.

1909777997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15752961, while the sum is 65.

The square root of 1909777997 is about 43701.0068190654. The cubic root of 1909777997 is about 1240.6833722359.

The spelling of 1909777997 in words is "one billion, nine hundred nine million, seven hundred seventy-seven thousand, nine hundred ninety-seven".