2109125861 has 2 divisors, whose sum is σ = 2109125862. Its totient is φ = 2109125860.

The previous prime is 2109125857. The next prime is 2109125881. The reversal of 2109125861 is 1685219012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1448944225 + 660181636 = 38065^2 + 25694^2 .

It is a cyclic number.

It is not a de Polignac number, because 2109125861 - 2² = 2109125857 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2109125881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1054562930 + 1054562931.

It is an arithmetic number, because the mean of its divisors is an integer number (1054562931).

Almost surely, 2^2109125861 is an apocalyptic number.

It is an amenable number.

2109125861 is a deficient number, since it is larger than the sum of its proper divisors (1).

2109125861 is an equidigital number, since it uses as much as digits as its factorization.

2109125861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 35.

The square root of 2109125861 is about 45925.2203152037. The cubic root of 2109125861 is about 1282.4314665591.

The spelling of 2109125861 in words is "two billion, one hundred nine million, one hundred twenty-five thousand, eight hundred sixty-one".