2019817861 has 2 divisors, whose sum is σ = 2019817862. Its totient is φ = 2019817860.

The previous prime is 2019817837. The next prime is 2019817873. The reversal of 2019817861 is 1687189102.

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., 1812630625 + 207187236 = 42575^2 + 14394^2 .

It is a cyclic number.

It is not a de Polignac number, because 2019817861 - 2¹⁵ = 2019785093 is a prime.

It is a super-2 number, since 2×2019817861² = 8159328383229230642, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2019817061) 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, 1009908930 + 1009908931.

It is an arithmetic number, because the mean of its divisors is an integer number (1009908931).

Almost surely, 2^2019817861 is an apocalyptic number.

It is an amenable number.

2019817861 is a deficient number, since it is larger than the sum of its proper divisors (1).

2019817861 is an equidigital number, since it uses as much as digits as its factorization.

2019817861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48384, while the sum is 43.

The square root of 2019817861 is about 44942.3837930299. The cubic root of 2019817861 is about 1264.0688698004.

The spelling of 2019817861 in words is "two billion, nineteen million, eight hundred seventeen thousand, eight hundred sixty-one".