1221669 has 8 divisors (see below), whose sum is σ = 1809920. Its totient is φ = 814428.

The previous prime is 1221667. The next prime is 1221707. The reversal of 1221669 is 9661221.

It is not a de Polignac number, because 1221669 - 2¹ = 1221667 is a prime.

It is a super-2 number, since 2×1221669² = 2984950291122, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 45247 = 1221669 / (1 + 2 + 2 + 1 + 6 + 6 + 9).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22597 + ... + 22650.

It is an arithmetic number, because the mean of its divisors is an integer number (226240).

2^1221669 is an apocalyptic number.

It is an amenable number.

1221669 is a deficient number, since it is larger than the sum of its proper divisors (588251).

1221669 is an equidigital number, since it uses as much as digits as its factorization.

1221669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45256 (or 45250 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 1221669 is about 1105.2913643017. The cubic root of 1221669 is about 106.9016769356.

The spelling of 1221669 in words is "one million, two hundred twenty-one thousand, six hundred sixty-nine".