1191671561 has 8 divisors (see below), whose sum is σ = 1244206464. Its totient is φ = 1139196960.

The previous prime is 1191671549. The next prime is 1191671563. The reversal of 1191671561 is 1651761911.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1191671561 - 2¹⁴ = 1191655177 is a prime.

It is a super-3 number, since 3×1191671561³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1191671563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27965 + ... + 56261.

It is an arithmetic number, because the mean of its divisors is an integer number (155525808).

Almost surely, 2^1191671561 is an apocalyptic number.

It is an amenable number.

1191671561 is a deficient number, since it is larger than the sum of its proper divisors (52534903).

1191671561 is a wasteful number, since it uses less digits than its factorization.

1191671561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30151.

The product of its digits is 11340, while the sum is 38.

The square root of 1191671561 is about 34520.5961854659. The cubic root of 1191671561 is about 1060.1944466472.

The spelling of 1191671561 in words is "one billion, one hundred ninety-one million, six hundred seventy-one thousand, five hundred sixty-one".