1221000001 has 8 divisors (see below), whose sum is σ = 1315336064. Its totient is φ = 1126722960.

The previous prime is 1220999999. The next prime is 1221000017. The reversal of 1221000001 is 1000001221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221000001 - 2¹ = 1220999999 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221000031) 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, 34270 + ... + 60136.

It is an arithmetic number, because the mean of its divisors is an integer number (164417008).

Almost surely, 2^1221000001 is an apocalyptic number.

It is an amenable number.

1221000001 is a deficient number, since it is larger than the sum of its proper divisors (94336063).

1221000001 is a wasteful number, since it uses less digits than its factorization.

1221000001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29511.

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

The square root of 1221000001 is about 34942.8104336214. The cubic root of 1221000001 is about 1068.8215987235.

Adding to 1221000001 its reverse (1000001221), we get a palindrome (2221001222).

The spelling of 1221000001 in words is "one billion, two hundred twenty-one million, one", and thus it is an aban number.