1216912171 has 18 divisors (see below), whose sum is σ = 1314288780. Its totient is φ = 1123621200.

The previous prime is 1216912157. The next prime is 1216912187. The reversal of 1216912171 is 1712196121.

It is not a de Polignac number, because 1216912171 - 2¹⁷ = 1216781099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216912121) by changing a digit.

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 17 ways as a sum of consecutive naturals, for example, 8058946 + ... + 8059096.

Almost surely, 2^1216912171 is an apocalyptic number.

1216912171 is a deficient number, since it is larger than the sum of its proper divisors (97376609).

1216912171 is an frugal number, since it uses more digits than its factorization.

1216912171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 427 (or 223 counting only the distinct ones).

The product of its digits is 1512, while the sum is 31.

The square root of 1216912171 is about 34884.2682451560. The cubic root of 1216912171 is about 1067.6274829789.

The spelling of 1216912171 in words is "one billion, two hundred sixteen million, nine hundred twelve thousand, one hundred seventy-one".