1221965 has 4 divisors (see below), whose sum is σ = 1466364. Its totient is φ = 977568.

The previous prime is 1221959. The next prime is 1221971. The reversal of 1221965 is 5691221.

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

It is an interprime number because it is at equal distance from previous prime (1221959) and next prime (1221971).

It can be written as a sum of positive squares in 2 ways, for example, as 635209 + 586756 = 797^2 + 766^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221965 - 2¹⁶ = 1156429 is a prime.

It is a super-2 number, since 2×1221965² = 2986396922450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122192 + ... + 122201.

It is an arithmetic number, because the mean of its divisors is an integer number (366591).

2^1221965 is an apocalyptic number.

It is an amenable number.

1221965 is a deficient number, since it is larger than the sum of its proper divisors (244399).

1221965 is an equidigital number, since it uses as much as digits as its factorization.

1221965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244398.

The product of its digits is 1080, while the sum is 26.

The square root of 1221965 is about 1105.4252575367. The cubic root of 1221965 is about 106.9103100272.

The spelling of 1221965 in words is "one million, two hundred twenty-one thousand, nine hundred sixty-five".