1221001 has 4 divisors (see below), whose sum is σ = 1274112. Its totient is φ = 1167892.

The previous prime is 1220993. The next prime is 1221019. The reversal of 1221001 is 1001221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1001221 = 13 ⋅77017.

It is a cyclic number.

It is not a de Polignac number, because 1221001 - 2³ = 1220993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221061) 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, 26521 + ... + 26566.

It is an arithmetic number, because the mean of its divisors is an integer number (318528).

2^1221001 is an apocalyptic number.

It is an amenable number.

1221001 is a deficient number, since it is larger than the sum of its proper divisors (53111).

1221001 is an equidigital number, since it uses as much as digits as its factorization.

1221001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53110.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 1221001 is about 1104.9891402181. The cubic root of 1221001 is about 106.8821890220.

Adding to 1221001 its reverse (1001221), we get a palindrome (2222222).

The spelling of 1221001 in words is "one million, two hundred twenty-one thousand, one".