1216232531 has 4 divisors (see below), whose sum is σ = 1218029712. Its totient is φ = 1214435352.

The previous prime is 1216232519. The next prime is 1216232533. The reversal of 1216232531 is 1352326121.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1216232531 - 2⁶ = 1216232467 is a prime.

It is a super-2 number, since 2×1216232531² = 2958443138925331922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1216232531.

It is not an unprimeable number, because it can be changed into a prime (1216232533) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 897575 + ... + 898928.

It is an arithmetic number, because the mean of its divisors is an integer number (304507428).

Almost surely, 2^1216232531 is an apocalyptic number.

1216232531 is a deficient number, since it is larger than the sum of its proper divisors (1797181).

1216232531 is an equidigital number, since it uses as much as digits as its factorization.

1216232531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1797180.

The product of its digits is 2160, while the sum is 26.

The square root of 1216232531 is about 34874.5255308226. The cubic root of 1216232531 is about 1067.4286909095.

Adding to 1216232531 its reverse (1352326121), we get a palindrome (2568558652).

The spelling of 1216232531 in words is "one billion, two hundred sixteen million, two hundred thirty-two thousand, five hundred thirty-one".