1213166645 has 4 divisors (see below), whose sum is σ = 1455799980. Its totient is φ = 970533312.

The previous prime is 1213166641. The next prime is 1213166711. The reversal of 1213166645 is 5466613121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 909082801 + 304083844 = 30151^2 + 17438^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213166645 - 2² = 1213166641 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213166641) 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, 121316660 + ... + 121316669.

It is an arithmetic number, because the mean of its divisors is an integer number (363949995).

Almost surely, 2^1213166645 is an apocalyptic number.

It is an amenable number.

1213166645 is a deficient number, since it is larger than the sum of its proper divisors (242633335).

1213166645 is an equidigital number, since it uses as much as digits as its factorization.

1213166645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242633334.

The product of its digits is 25920, while the sum is 35.

The square root of 1213166645 is about 34830.5418418950. The cubic root of 1213166645 is about 1066.5310093865.

Adding to 1213166645 its reverse (5466613121), we get a palindrome (6679779766).

The spelling of 1213166645 in words is "one billion, two hundred thirteen million, one hundred sixty-six thousand, six hundred forty-five".