2105770781 has 2 divisors, whose sum is σ = 2105770782. Its totient is φ = 2105770780.

The previous prime is 2105770747. The next prime is 2105770787. The reversal of 2105770781 is 1870775012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1877488900 + 228281881 = 43330^2 + 15109^2 .

It is a cyclic number.

It is not a de Polignac number, because 2105770781 - 2⁶ = 2105770717 is a prime.

It is a super-2 number, since 2×2105770781² = 8868541164226699922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2105770787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1052885390 + 1052885391.

It is an arithmetic number, because the mean of its divisors is an integer number (1052885391).

Almost surely, 2^2105770781 is an apocalyptic number.

It is an amenable number.

2105770781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2105770781 is an equidigital number, since it uses as much as digits as its factorization.

2105770781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27440, while the sum is 38.

The square root of 2105770781 is about 45888.6781352438. The cubic root of 2105770781 is about 1281.7510988074.

The spelling of 2105770781 in words is "two billion, one hundred five million, seven hundred seventy thousand, seven hundred eighty-one".