1211666705 has 4 divisors (see below), whose sum is σ = 1454000052. Its totient is φ = 969333360.

The previous prime is 1211666681. The next prime is 1211666711. The reversal of 1211666705 is 5076661121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 323388289 + 888278416 = 17983^2 + 29804^2 .

It is not a de Polignac number, because 1211666705 - 2¹⁰ = 1211665681 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121166666 + ... + 121166675.

It is an arithmetic number, because the mean of its divisors is an integer number (363500013).

Almost surely, 2^1211666705 is an apocalyptic number.

It is an amenable number.

1211666705 is a deficient number, since it is larger than the sum of its proper divisors (242333347).

1211666705 is an equidigital number, since it uses as much as digits as its factorization.

1211666705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242333346.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 1211666705 is about 34809.0032175585. The cubic root of 1211666705 is about 1066.0912807703.

The spelling of 1211666705 in words is "one billion, two hundred eleven million, six hundred sixty-six thousand, seven hundred five".