1221943 has 4 divisors (see below), whose sum is σ = 1293840. Its totient is φ = 1150048.

The previous prime is 1221937. The next prime is 1221959. The reversal of 1221943 is 3491221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3491221 = 521 ⋅6701.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221943 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35923 + ... + 35956.

It is an arithmetic number, because the mean of its divisors is an integer number (323460).

2^1221943 is an apocalyptic number.

1221943 is a deficient number, since it is larger than the sum of its proper divisors (71897).

1221943 is an equidigital number, since it uses as much as digits as its factorization.

1221943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71896.

The product of its digits is 432, while the sum is 22.

The square root of 1221943 is about 1105.4153065703. The cubic root of 1221943 is about 106.9096684265.

It can be divided in two parts, 1221 and 943, that multiplied together give a triangular number (1151403 = T₁₅₁₇).

The spelling of 1221943 in words is "one million, two hundred twenty-one thousand, nine hundred forty-three".