1212105251 has 4 divisors (see below), whose sum is σ = 1385263152. Its totient is φ = 1038947352.

The previous prime is 1212105233. The next prime is 1212105259. The reversal of 1212105251 is 1525012121.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1212105251 - 2¹⁸ = 1211843107 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1212105259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86578940 + ... + 86578953.

It is an arithmetic number, because the mean of its divisors is an integer number (346315788).

Almost surely, 2^1212105251 is an apocalyptic number.

1212105251 is a deficient number, since it is larger than the sum of its proper divisors (173157901).

1212105251 is an equidigital number, since it uses as much as digits as its factorization.

1212105251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173157900.

The product of its (nonzero) digits is 200, while the sum is 20.

The square root of 1212105251 is about 34815.3019662332. The cubic root of 1212105251 is about 1066.2198842525.

Adding to 1212105251 its reverse (1525012121), we get a palindrome (2737117372).

The spelling of 1212105251 in words is "one billion, two hundred twelve million, one hundred five thousand, two hundred fifty-one".