1221220601 has 4 divisors (see below), whose sum is σ = 1223708304. Its totient is φ = 1218732900.

The previous prime is 1221220571. The next prime is 1221220621. The reversal of 1221220601 is 1060221221.

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: 1060221221 = 2309 ⋅459169.

It is a cyclic number.

It is not a de Polignac number, because 1221220601 - 2¹⁰ = 1221219577 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221220601.

It is not an unprimeable number, because it can be changed into a prime (1221220621) 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, 1243115 + ... + 1244096.

It is an arithmetic number, because the mean of its divisors is an integer number (305927076).

Almost surely, 2^1221220601 is an apocalyptic number.

It is an amenable number.

1221220601 is a deficient number, since it is larger than the sum of its proper divisors (2487703).

1221220601 is an equidigital number, since it uses as much as digits as its factorization.

1221220601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2487702.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 1221220601 is about 34945.9668774524. The cubic root of 1221220601 is about 1068.8859634098.

Adding to 1221220601 its reverse (1060221221), we get a palindrome (2281441822).

The spelling of 1221220601 in words is "one billion, two hundred twenty-one million, two hundred twenty thousand, six hundred one".