1221406 has 4 divisors (see below), whose sum is σ = 1832112. Its totient is φ = 610702.

The previous prime is 1221391. The next prime is 1221421. The reversal of 1221406 is 6041221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6041221 = 19 ⋅317959.

It is an interprime number because it is at equal distance from previous prime (1221391) and next prime (1221421).

It is a self number, because there is not a number n which added to its sum of digits gives 1221406.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 305350 + ... + 305353.

It is an arithmetic number, because the mean of its divisors is an integer number (458028).

2^1221406 is an apocalyptic number.

1221406 is a deficient number, since it is larger than the sum of its proper divisors (610706).

1221406 is an equidigital number, since it uses as much as digits as its factorization.

1221406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 610705.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 1221406 is about 1105.1723847437. The cubic root of 1221406 is about 106.8940051470.

Adding to 1221406 its reverse (6041221), we get a palindrome (7262627).

The spelling of 1221406 in words is "one million, two hundred twenty-one thousand, four hundred six".