1212165251 has 16 divisors (see below), whose sum is σ = 1417160448. Its totient is φ = 1025560800.

The previous prime is 1212165239. The next prime is 1212165271. The reversal of 1212165251 is 1525612121.

It is not a de Polignac number, because 1212165251 - 2⁶ = 1212165187 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1212165251.

It is not an unprimeable number, because it can be changed into a prime (1212165271) 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, 55385 + ... + 74106.

It is an arithmetic number, because the mean of its divisors is an integer number (88572528).

Almost surely, 2^1212165251 is an apocalyptic number.

1212165251 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1212165251 is a deficient number, since it is larger than the sum of its proper divisors (204995197).

1212165251 is a wasteful number, since it uses less digits than its factorization.

1212165251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129562.

The product of its digits is 1200, while the sum is 26.

The square root of 1212165251 is about 34816.1636456402. The cubic root of 1212165251 is about 1066.2374768220.

Adding to 1212165251 its reverse (1525612121), we get a palindrome (2737777372).

The spelling of 1212165251 in words is "one billion, two hundred twelve million, one hundred sixty-five thousand, two hundred fifty-one".