2111862581 has 2 divisors, whose sum is σ = 2111862582. Its totient is φ = 2111862580.

The previous prime is 2111862551. The next prime is 2111862601. The reversal of 2111862581 is 1852681112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1891815025 + 220047556 = 43495^2 + 14834^2 .

It is a cyclic number.

It is not a de Polignac number, because 2111862581 - 2¹⁴ = 2111846197 is a prime.

It is a super-2 number, since 2×2111862581² = 8919927122055963122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2111862551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1055931290 + 1055931291.

It is an arithmetic number, because the mean of its divisors is an integer number (1055931291).

Almost surely, 2^2111862581 is an apocalyptic number.

It is an amenable number.

2111862581 is a deficient number, since it is larger than the sum of its proper divisors (1).

2111862581 is an equidigital number, since it uses as much as digits as its factorization.

2111862581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7680, while the sum is 35.

The square root of 2111862581 is about 45955.0060493958. The cubic root of 2111862581 is about 1282.9859046170.

The spelling of 2111862581 in words is "two billion, one hundred eleven million, eight hundred sixty-two thousand, five hundred eighty-one".