1881001861 has 2 divisors, whose sum is σ = 1881001862. Its totient is φ = 1881001860.

The previous prime is 1881001841. The next prime is 1881001879. The reversal of 1881001861 is 1681001881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1870562500 + 10439361 = 43250^2 + 3231^2 .

It is a cyclic number.

It is not a de Polignac number, because 1881001861 - 2¹³ = 1880993669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1881001831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 940500930 + 940500931.

It is an arithmetic number, because the mean of its divisors is an integer number (940500931).

Almost surely, 2^1881001861 is an apocalyptic number.

It is an amenable number.

1881001861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1881001861 is an equidigital number, since it uses as much as digits as its factorization.

1881001861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3072, while the sum is 34.

The square root of 1881001861 is about 43370.5183390745. The cubic root of 1881001861 is about 1234.4203568579.

The spelling of 1881001861 in words is "one billion, eight hundred eighty-one million, one thousand, eight hundred sixty-one".