1216561234 has 8 divisors (see below), whose sum is σ = 2085533568. Its totient is φ = 521383380.

The previous prime is 1216561193. The next prime is 1216561253. The reversal of 1216561234 is 4321656121.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an alternating number because its digits alternate between odd and even.

It is a junction number, because it is equal to n+sod(n) for n = 1216561196 and 1216561205.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43448602 + ... + 43448629.

It is an arithmetic number, because the mean of its divisors is an integer number (260691696).

Almost surely, 2^1216561234 is an apocalyptic number.

1216561234 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

1216561234 is a deficient number, since it is larger than the sum of its proper divisors (868972334).

1216561234 is an equidigital number, since it uses as much as digits as its factorization.

1216561234 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86897240.

The product of its digits is 8640, while the sum is 31.

The square root of 1216561234 is about 34879.2378643800. The cubic root of 1216561234 is about 1067.5248445095.

The spelling of 1216561234 in words is "one billion, two hundred sixteen million, five hundred sixty-one thousand, two hundred thirty-four".