1216542263 has 4 divisors (see below), whose sum is σ = 1217046768. Its totient is φ = 1216037760.

The previous prime is 1216542227. The next prime is 1216542319. The reversal of 1216542263 is 3622456121.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1216542263 is a prime.

It is a super-2 number, since 2×1216542263² = 2959950155330322338, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216545263) 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, 248618 + ... + 253463.

It is an arithmetic number, because the mean of its divisors is an integer number (304261692).

Almost surely, 2^1216542263 is an apocalyptic number.

1216542263 is a deficient number, since it is larger than the sum of its proper divisors (504505).

1216542263 is an equidigital number, since it uses as much as digits as its factorization.

1216542263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 504504.

The product of its digits is 17280, while the sum is 32.

The square root of 1216542263 is about 34878.9659107033. The cubic root of 1216542263 is about 1067.5192955029.

Adding to 1216542263 its reverse (3622456121), we get a palindrome (4838998384).

The spelling of 1216542263 in words is "one billion, two hundred sixteen million, five hundred forty-two thousand, two hundred sixty-three".