2101656409 has 2 divisors, whose sum is σ = 2101656410. Its totient is φ = 2101656408.

The previous prime is 2101656283. The next prime is 2101656421. The reversal of 2101656409 is 9046561012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1183566409 + 918090000 = 34403^2 + 30300^2 .

It is a cyclic number.

It is not a de Polignac number, because 2101656409 - 2⁷ = 2101656281 is a prime.

It is a super-2 number, since 2×2101656409² = 8833919322981550562, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2101756409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1050828204 + 1050828205.

It is an arithmetic number, because the mean of its divisors is an integer number (1050828205).

Almost surely, 2^2101656409 is an apocalyptic number.

It is an amenable number.

2101656409 is a deficient number, since it is larger than the sum of its proper divisors (1).

2101656409 is an equidigital number, since it uses as much as digits as its factorization.

2101656409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 2101656409 is about 45843.8262910067. The cubic root of 2101656409 is about 1280.9157690189.

The spelling of 2101656409 in words is "two billion, one hundred one million, six hundred fifty-six thousand, four hundred nine".