1221165 has 24 divisors (see below), whose sum is σ = 2310048. Its totient is φ = 591840.

The previous prime is 1221163. The next prime is 1221167. The reversal of 1221165 is 5611221.

It is an interprime number because it is at equal distance from previous prime (1221163) and next prime (1221167).

It is not a de Polignac number, because 1221165 - 2¹ = 1221163 is a prime.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221163) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 739 + ... + 1728.

It is an arithmetic number, because the mean of its divisors is an integer number (96252).

2^1221165 is an apocalyptic number.

1221165 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221165 is a deficient number, since it is larger than the sum of its proper divisors (1088883).

1221165 is a wasteful number, since it uses less digits than its factorization.

1221165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2489 (or 2486 counting only the distinct ones).

The product of its digits is 120, while the sum is 18.

The square root of 1221165 is about 1105.0633466005. The cubic root of 1221165 is about 106.8869741380.

Adding to 1221165 its reverse (5611221), we get a palindrome (6832386).

The spelling of 1221165 in words is "one million, two hundred twenty-one thousand, one hundred sixty-five".