1212561331 has 4 divisors (see below), whose sum is σ = 1212667000. Its totient is φ = 1212455664.

The previous prime is 1212561281. The next prime is 1212561367. The reversal of 1212561331 is 1331652121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1331652121 = 9161 ⋅145361.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1212561331 is a prime.

It is a super-2 number, since 2×1212561331² = 2940609962872983122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1212561296 and 1212561305.

It is not an unprimeable number, because it can be changed into a prime (1212561391) 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, 33186 + ... + 59383.

It is an arithmetic number, because the mean of its divisors is an integer number (303166750).

Almost surely, 2^1212561331 is an apocalyptic number.

1212561331 is a deficient number, since it is larger than the sum of its proper divisors (105669).

1212561331 is an equidigital number, since it uses as much as digits as its factorization.

1212561331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105668.

The product of its digits is 1080, while the sum is 25.

The square root of 1212561331 is about 34821.8513436606. The cubic root of 1212561331 is about 1066.3535966745.

The spelling of 1212561331 in words is "one billion, two hundred twelve million, five hundred sixty-one thousand, three hundred thirty-one".