1166155921 has 4 divisors (see below), whose sum is σ = 1332749632. Its totient is φ = 999562212.

The previous prime is 1166155909. The next prime is 1166155931. The reversal of 1166155921 is 1295516611.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1166155921 - 2⁵ = 1166155889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1166155931) 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, 83296845 + ... + 83296858.

It is an arithmetic number, because the mean of its divisors is an integer number (333187408).

Almost surely, 2^1166155921 is an apocalyptic number.

It is an amenable number.

1166155921 is a deficient number, since it is larger than the sum of its proper divisors (166593711).

1166155921 is an equidigital number, since it uses as much as digits as its factorization.

1166155921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166593710.

The product of its digits is 16200, while the sum is 37.

The square root of 1166155921 is about 34149.0251837443. The cubic root of 1166155921 is about 1052.5729556009.

The spelling of 1166155921 in words is "one billion, one hundred sixty-six million, one hundred fifty-five thousand, nine hundred twenty-one".