11705566921 has 4 divisors (see below), whose sum is σ = 11751114132. Its totient is φ = 11660019712.

The previous prime is 11705566891. The next prime is 11705566933. The reversal of 11705566921 is 12966550711.

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 11633995321 + 71571600 = 107861^2 + 8460^2 .

It is a cyclic number.

It is not a de Polignac number, because 11705566921 - 2⁷ = 11705566793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11705566021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22773220 + ... + 22773733.

It is an arithmetic number, because the mean of its divisors is an integer number (2937778533).

Almost surely, 2^11705566921 is an apocalyptic number.

It is an amenable number.

11705566921 is a deficient number, since it is larger than the sum of its proper divisors (45547211).

11705566921 is an equidigital number, since it uses as much as digits as its factorization.

11705566921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45547210.

The product of its (nonzero) digits is 113400, while the sum is 43.

The spelling of 11705566921 in words is "eleven billion, seven hundred five million, five hundred sixty-six thousand, nine hundred twenty-one".