1212551555 has 4 divisors (see below), whose sum is σ = 1455061872. Its totient is φ = 970041240.

The previous prime is 1212551551. The next prime is 1212551563. The reversal of 1212551555 is 5551552121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5551552121 = 12391 ⋅448031.

It is not a de Polignac number, because 1212551555 - 2² = 1212551551 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1212551551) 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, 121255151 + ... + 121255160.

It is an arithmetic number, because the mean of its divisors is an integer number (363765468).

Almost surely, 2^1212551555 is an apocalyptic number.

1212551555 is a deficient number, since it is larger than the sum of its proper divisors (242510317).

1212551555 is an equidigital number, since it uses as much as digits as its factorization.

1212551555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242510316.

The product of its digits is 12500, while the sum is 32.

The square root of 1212551555 is about 34821.7109717486. The cubic root of 1212551555 is about 1066.3507309223.

The spelling of 1212551555 in words is "one billion, two hundred twelve million, five hundred fifty-one thousand, five hundred fifty-five".