1966221 has 8 divisors (see below), whose sum is σ = 2912960. Its totient is φ = 1310796.

The previous prime is 1966219. The next prime is 1966241. The reversal of 1966221 is 1226691.

It is not a de Polignac number, because 1966221 - 2¹ = 1966219 is a prime.

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: 72823 = 1966221 / (1 + 9 + 6 + 6 + 2 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1966241) 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, 36385 + ... + 36438.

It is an arithmetic number, because the mean of its divisors is an integer number (364120).

2^1966221 is an apocalyptic number.

It is an amenable number.

1966221 is a deficient number, since it is larger than the sum of its proper divisors (946739).

1966221 is an equidigital number, since it uses as much as digits as its factorization.

1966221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72832 (or 72826 counting only the distinct ones).

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

The square root of 1966221 is about 1402.2200255309. The cubic root of 1966221 is about 125.2787592176.

It can be divided in two parts, 19662 and 21, that added together give a 9-th power (19683 = 3⁹).

The spelling of 1966221 in words is "one million, nine hundred sixty-six thousand, two hundred twenty-one".