2111670511781 has 2 divisors, whose sum is σ = 2111670511782. Its totient is φ = 2111670511780.

The previous prime is 2111670511673. The next prime is 2111670511789. The reversal of 2111670511781 is 1871150761112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1219323892900 + 892346618881 = 1104230^2 + 944641^2 .

It is a cyclic number.

It is not a de Polignac number, because 2111670511781 - 2¹⁰ = 2111670510757 is a prime.

It is a super-2 number, since 2×2111670511781² (a number of 25 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2111670511789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1055835255890 + 1055835255891.

It is an arithmetic number, because the mean of its divisors is an integer number (1055835255891).

Almost surely, 2^{2111670511781} is an apocalyptic number.

It is an amenable number.

2111670511781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2111670511781 is an equidigital number, since it uses as much as digits as its factorization.

2111670511781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23520, while the sum is 41.

The spelling of 2111670511781 in words is "two trillion, one hundred eleven billion, six hundred seventy million, five hundred eleven thousand, seven hundred eighty-one".