1216081867 has 16 divisors (see below), whose sum is σ = 1632782592. Its totient is φ = 874703520.

The previous prime is 1216081817. The next prime is 1216081883. The reversal of 1216081867 is 7681806121.

It is a cyclic number.

It is not a de Polignac number, because 1216081867 - 2⁷ = 1216081739 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1216081817) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 606433 + ... + 608434.

It is an arithmetic number, because the mean of its divisors is an integer number (102048912).

Almost surely, 2^1216081867 is an apocalyptic number.

1216081867 is a deficient number, since it is larger than the sum of its proper divisors (416700725).

1216081867 is a wasteful number, since it uses less digits than its factorization.

1216081867 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1214898.

The product of its (nonzero) digits is 32256, while the sum is 40.

The square root of 1216081867 is about 34872.3653771866. The cubic root of 1216081867 is about 1067.3846122449.

Adding to 1216081867 its reverse (7681806121), we get a palindrome (8897887988).

The spelling of 1216081867 in words is "one billion, two hundred sixteen million, eighty-one thousand, eight hundred sixty-seven".