1199212561 has 4 divisors (see below), whose sum is σ = 1199296624. Its totient is φ = 1199128500.

The previous prime is 1199212543. The next prime is 1199212577. The reversal of 1199212561 is 1652129911.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1199212561 - 2⁵ = 1199212529 is a prime.

It is a super-2 number, since 2×1199212561² = 2876221532920357442, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1199212561.

It is not an unprimeable number, because it can be changed into a prime (1199212541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14715 + ... + 51136.

It is an arithmetic number, because the mean of its divisors is an integer number (299824156).

Almost surely, 2^1199212561 is an apocalyptic number.

It is an amenable number.

1199212561 is a deficient number, since it is larger than the sum of its proper divisors (84063).

1199212561 is an equidigital number, since it uses as much as digits as its factorization.

1199212561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84062.

The product of its digits is 9720, while the sum is 37.

The square root of 1199212561 is about 34629.6485832588. The cubic root of 1199212561 is about 1062.4260797662.

The spelling of 1199212561 in words is "one billion, one hundred ninety-nine million, two hundred twelve thousand, five hundred sixty-one".