1200215555 has 144 divisors (see below), whose sum is σ = 2056202496. Its totient is φ = 663505920.

The previous prime is 1200215551. The next prime is 1200215563. The reversal of 1200215555 is 5555120021.

It is not a de Polignac number, because 1200215555 - 2² = 1200215551 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1200215551) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 17913632 + ... + 17913698.

It is an arithmetic number, because the mean of its divisors is an integer number (14279184).

Almost surely, 2^1200215555 is an apocalyptic number.

1200215555 is a deficient number, since it is larger than the sum of its proper divisors (855986941).

1200215555 is a wasteful number, since it uses less digits than its factorization.

1200215555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 2500, while the sum is 26.

The square root of 1200215555 is about 34644.1272801033. The cubic root of 1200215555 is about 1062.7221935309.

Adding to 1200215555 its reverse (5555120021), we get a palindrome (6755335576).

The spelling of 1200215555 in words is "one billion, two hundred million, two hundred fifteen thousand, five hundred fifty-five".