1213342561 has 4 divisors (see below), whose sum is σ = 1242936324. Its totient is φ = 1183748800.

The previous prime is 1213342541. The next prime is 1213342583. The reversal of 1213342561 is 1652433121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1652433121 = 97 ⋅17035393.

It can be written as a sum of positive squares in 2 ways, for example, as 737448336 + 475894225 = 27156^2 + 21815^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213342561 - 2¹⁹ = 1212818273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1213342541) 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, 14796820 + ... + 14796901.

It is an arithmetic number, because the mean of its divisors is an integer number (310734081).

Almost surely, 2^1213342561 is an apocalyptic number.

It is an amenable number.

1213342561 is a deficient number, since it is larger than the sum of its proper divisors (29593763).

1213342561 is an equidigital number, since it uses as much as digits as its factorization.

1213342561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29593762.

The product of its digits is 4320, while the sum is 28.

The square root of 1213342561 is about 34833.0670627781. The cubic root of 1213342561 is about 1066.5825578971.

Adding to 1213342561 its reverse (1652433121), we get a palindrome (2865775682).

The spelling of 1213342561 in words is "one billion, two hundred thirteen million, three hundred forty-two thousand, five hundred sixty-one".