1216155553 has 16 divisors (see below), whose sum is σ = 1319201920. Its totient is φ = 1117224576.

The previous prime is 1216155547. The next prime is 1216155559. The reversal of 1216155553 is 3555516121.

It is an interprime number because it is at equal distance from previous prime (1216155547) and next prime (1216155559).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1216155553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1216155559) 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, 217276 + ... + 222802.

It is an arithmetic number, because the mean of its divisors is an integer number (82450120).

Almost surely, 2^1216155553 is an apocalyptic number.

It is an amenable number.

1216155553 is a deficient number, since it is larger than the sum of its proper divisors (103046367).

1216155553 is a wasteful number, since it uses less digits than its factorization.

1216155553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5896.

The product of its digits is 22500, while the sum is 34.

The square root of 1216155553 is about 34873.4218711041. The cubic root of 1216155553 is about 1067.4061704738.

The spelling of 1216155553 in words is "one billion, two hundred sixteen million, one hundred fifty-five thousand, five hundred fifty-three".