1216543534 has 4 divisors (see below), whose sum is σ = 1824815304. Its totient is φ = 608271766.

The previous prime is 1216543519. The next prime is 1216543543. The reversal of 1216543534 is 4353456121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 4353456121 = 7 ⋅621922303.

It is a self number, because there is not a number n which added to its sum of digits gives 1216543534.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 304135882 + ... + 304135885.

It is an arithmetic number, because the mean of its divisors is an integer number (456203826).

Almost surely, 2^1216543534 is an apocalyptic number.

1216543534 is a deficient number, since it is larger than the sum of its proper divisors (608271770).

1216543534 is an equidigital number, since it uses as much as digits as its factorization.

1216543534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 608271769.

The product of its digits is 43200, while the sum is 34.

The square root of 1216543534 is about 34878.9841308488. The cubic root of 1216543534 is about 1067.5196672714.

Adding to 1216543534 its reverse (4353456121), we get a palindrome (5569999655).

The spelling of 1216543534 in words is "one billion, two hundred sixteen million, five hundred forty-three thousand, five hundred thirty-four".