1213166665 has 8 divisors (see below), whose sum is σ = 1541435400. Its totient is φ = 913443072.

The previous prime is 1213166641. The next prime is 1213166711. The reversal of 1213166665 is 5666613121.

It can be written as a sum of positive squares in 4 ways, for example, as 141324544 + 1071842121 = 11888^2 + 32739^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1213166665 - 2⁹ = 1213166153 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7136190 + ... + 7136359.

It is an arithmetic number, because the mean of its divisors is an integer number (192679425).

Almost surely, 2^1213166665 is an apocalyptic number.

It is an amenable number.

1213166665 is a deficient number, since it is larger than the sum of its proper divisors (328268735).

1213166665 is a wasteful number, since it uses less digits than its factorization.

1213166665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14272571.

The product of its digits is 38880, while the sum is 37.

The square root of 1213166665 is about 34830.5421289994. The cubic root of 1213166665 is about 1066.5310152473.

Adding to 1213166665 its reverse (5666613121), we get a palindrome (6879779786).

The spelling of 1213166665 in words is "one billion, two hundred thirteen million, one hundred sixty-six thousand, six hundred sixty-five".