1216643165 has 8 divisors (see below), whose sum is σ = 1545852600. Its totient is φ = 916060672.

The previous prime is 1216643137. The next prime is 1216643191. The reversal of 1216643165 is 5613466121.

It can be written as a sum of positive squares in 4 ways, for example, as 42758521 + 1173884644 = 6539^2 + 34262^2 .

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 1216643165 - 2⁶ = 1216643101 is a prime.

It is a congruent number.

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, 7156640 + ... + 7156809.

It is an arithmetic number, because the mean of its divisors is an integer number (193231575).

Almost surely, 2^1216643165 is an apocalyptic number.

It is an amenable number.

1216643165 is a deficient number, since it is larger than the sum of its proper divisors (329209435).

1216643165 is a wasteful number, since it uses less digits than its factorization.

1216643165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14313471.

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

The square root of 1216643165 is about 34880.4123398792. The cubic root of 1216643165 is about 1067.5488086176.

The spelling of 1216643165 in words is "one billion, two hundred sixteen million, six hundred forty-three thousand, one hundred sixty-five".