2865557861 has 2 divisors, whose sum is σ = 2865557862. Its totient is φ = 2865557860.

The previous prime is 2865557813. The next prime is 2865557887. The reversal of 2865557861 is 1687555682.

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., 2754255361 + 111302500 = 52481^2 + 10550^2 .

It is a cyclic number.

It is not a de Polignac number, because 2865557861 - 2²⁶ = 2798448997 is a prime.

It is a super-3 number, since 3×2865557861³ (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 (2865557161) 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, 1432778930 + 1432778931.

It is an arithmetic number, because the mean of its divisors is an integer number (1432778931).

Almost surely, 2^2865557861 is an apocalyptic number.

It is an amenable number.

2865557861 is a deficient number, since it is larger than the sum of its proper divisors (1).

2865557861 is an equidigital number, since it uses as much as digits as its factorization.

2865557861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032000, while the sum is 53.

The square root of 2865557861 is about 53530.9056620566. The cubic root of 2865557861 is about 1420.3751341427.

The spelling of 2865557861 in words is "two billion, eight hundred sixty-five million, five hundred fifty-seven thousand, eight hundred sixty-one".