1861772069 has 2 divisors, whose sum is σ = 1861772070. Its totient is φ = 1861772068.

The previous prime is 1861772047. The next prime is 1861772083. The reversal of 1861772069 is 9602771681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1467273025 + 394499044 = 38305^2 + 19862^2 .

It is an emirp because it is prime and its reverse (9602771681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1861772069 - 2²⁰ = 1860723493 is a prime.

It is a super-3 number, since 3×1861772069³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1861772009) 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, 930886034 + 930886035.

It is an arithmetic number, because the mean of its divisors is an integer number (930886035).

Almost surely, 2^1861772069 is an apocalyptic number.

It is an amenable number.

1861772069 is a deficient number, since it is larger than the sum of its proper divisors (1).

1861772069 is an equidigital number, since it uses as much as digits as its factorization.

1861772069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 254016, while the sum is 47.

The square root of 1861772069 is about 43148.2568477569. The cubic root of 1861772069 is about 1230.1993791850.

The spelling of 1861772069 in words is "one billion, eight hundred sixty-one million, seven hundred seventy-two thousand, sixty-nine".