1216644815 has 8 divisors (see below), whose sum is σ = 1471119408. Its totient is φ = 965885440.

The previous prime is 1216644809. The next prime is 1216644829. The reversal of 1216644815 is 5184466121.

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

It is not a de Polignac number, because 1216644815 - 2⁴ = 1216644799 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 928082 + ... + 929391.

It is an arithmetic number, because the mean of its divisors is an integer number (183889926).

Almost surely, 2^1216644815 is an apocalyptic number.

1216644815 is a deficient number, since it is larger than the sum of its proper divisors (254474593).

1216644815 is a wasteful number, since it uses less digits than its factorization.

1216644815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1857609.

The product of its digits is 46080, while the sum is 38.

The square root of 1216644815 is about 34880.4359921145. The cubic root of 1216644815 is about 1067.5492912172.

The spelling of 1216644815 in words is "one billion, two hundred sixteen million, six hundred forty-four thousand, eight hundred fifteen".