2121705112761 has 40 divisors (see below), whose sum is σ = 3419394285384. Its totient is φ = 1303320222720.

The previous prime is 2121705112759. The next prime is 2121705112837. The reversal of 2121705112761 is 1672115071212.

It is a happy number.

2121705112761 is a `hidden beast` number, since 2 + 1 + 2 + 1 + 70 + 511 + 2 + 76 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 3571257600 + 2118133855161 = 59760^2 + 1455381^2 .

It is not a de Polignac number, because 2121705112761 - 2¹ = 2121705112759 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2121705112711) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1222200 + ... + 2395241.

Almost surely, 2^{2121705112761} is an apocalyptic number.

It is an amenable number.

2121705112761 is a deficient number, since it is larger than the sum of its proper divisors (1297689172623).

2121705112761 is a wasteful number, since it uses less digits than its factorization.

2121705112761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3618023 (or 3618014 counting only the distinct ones).

The product of its (nonzero) digits is 11760, while the sum is 36.

The spelling of 2121705112761 in words is "two trillion, one hundred twenty-one billion, seven hundred five million, one hundred twelve thousand, seven hundred sixty-one".