1212055665 has 16 divisors (see below), whose sum is σ = 1971082176. Its totient is φ = 635832000.

The previous prime is 1212055591. The next prime is 1212055673. The reversal of 1212055665 is 5665502121.

It is not a de Polignac number, because 1212055665 - 2²⁰ = 1211007089 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 661411 + ... + 663240.

It is an arithmetic number, because the mean of its divisors is an integer number (123192636).

Almost surely, 2^1212055665 is an apocalyptic number.

1212055665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1212055665 is a deficient number, since it is larger than the sum of its proper divisors (759026511).

1212055665 is a wasteful number, since it uses less digits than its factorization.

1212055665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1324720.

The product of its (nonzero) digits is 18000, while the sum is 33.

The square root of 1212055665 is about 34814.5898295528. The cubic root of 1212055665 is about 1066.2053447285.

Adding to 1212055665 its reverse (5665502121), we get a palindrome (6877557786).

The spelling of 1212055665 in words is "one billion, two hundred twelve million, fifty-five thousand, six hundred sixty-five".