1221510166 has 32 divisors (see below), whose sum is σ = 1914531840. Its totient is φ = 584097696.

The previous prime is 1221510161. The next prime is 1221510203. The reversal of 1221510166 is 6610151221.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221510166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221510161) 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 15 ways as a sum of consecutive naturals, for example, 764080 + ... + 765676.

It is an arithmetic number, because the mean of its divisors is an integer number (59829120).

Almost surely, 2^1221510166 is an apocalyptic number.

1221510166 is a deficient number, since it is larger than the sum of its proper divisors (693021674).

1221510166 is a wasteful number, since it uses less digits than its factorization.

1221510166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1828.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 1221510166 is about 34950.1096707864. The cubic root of 1221510166 is about 1068.9704383207.

Adding to 1221510166 its reverse (6610151221), we get a palindrome (7831661387).

The spelling of 1221510166 in words is "one billion, two hundred twenty-one million, five hundred ten thousand, one hundred sixty-six".