1191719521 has 4 divisors (see below), whose sum is σ = 1192524592. Its totient is φ = 1190914452.

The previous prime is 1191719471. The next prime is 1191719531. The reversal of 1191719521 is 1259171911.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1259171911 = 89 ⋅14147999.

It is a cyclic number.

It is not a de Polignac number, because 1191719521 - 2⁷ = 1191719393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1191719531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 400311 + ... + 403276.

It is an arithmetic number, because the mean of its divisors is an integer number (298131148).

Almost surely, 2^1191719521 is an apocalyptic number.

It is an amenable number.

1191719521 is a deficient number, since it is larger than the sum of its proper divisors (805071).

1191719521 is an equidigital number, since it uses as much as digits as its factorization.

1191719521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 805070.

The product of its digits is 5670, while the sum is 37.

The square root of 1191719521 is about 34521.2908362361. The cubic root of 1191719521 is about 1060.2086693143.

The spelling of 1191719521 in words is "one billion, one hundred ninety-one million, seven hundred nineteen thousand, five hundred twenty-one".