1221401 has 4 divisors (see below), whose sum is σ = 1225572. Its totient is φ = 1217232.

The previous prime is 1221391. The next prime is 1221421. The reversal of 1221401 is 1041221.

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

It can be written as a sum of positive squares in 2 ways, for example, as 697225 + 524176 = 835^2 + 724^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1610 + ... + 2243.

It is an arithmetic number, because the mean of its divisors is an integer number (306393).

2^1221401 is an apocalyptic number.

It is an amenable number.

1221401 is a deficient number, since it is larger than the sum of its proper divisors (4171).

1221401 is an equidigital number, since it uses as much as digits as its factorization.

1221401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4170.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 1221401 is about 1105.1701226508. The cubic root of 1221401 is about 106.8938592849.

Adding to 1221401 its reverse (1041221), we get a palindrome (2262622).

The spelling of 1221401 in words is "one million, two hundred twenty-one thousand, four hundred one".