1216236666 has 16 divisors (see below), whose sum is σ = 2472350688. Its totient is φ = 398766000.

The previous prime is 1216236653. The next prime is 1216236689. The reversal of 1216236666 is 6666326121.

1216236666 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a nude number because it is divisible by every one of its digits.

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, 1661160 + ... + 1661891.

It is an arithmetic number, because the mean of its divisors is an integer number (154521918).

Almost surely, 2^1216236666 is an apocalyptic number.

1216236666 is an abundant number, since it is smaller than the sum of its proper divisors (1256114022).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1216236666 is a wasteful number, since it uses less digits than its factorization.

1216236666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3323117.

The product of its digits is 93312, while the sum is 39.

The square root of 1216236666 is about 34874.5848147329. The cubic root of 1216236666 is about 1067.4299006049.

It can be divided in two parts, 12162 and 36666, that added together give a triangular number (48828 = T₃₁₂).

The spelling of 1216236666 in words is "one billion, two hundred sixteen million, two hundred thirty-six thousand, six hundred sixty-six".