1221100321 has 8 divisors (see below), whose sum is σ = 1400851584. Its totient is φ = 1042676160.

The previous prime is 1221100277. The next prime is 1221100339. The reversal of 1221100321 is 1230011221.

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 1221100321 - 2⁷ = 1221100193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221100351) 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, 329800 + ... + 333481.

It is an arithmetic number, because the mean of its divisors is an integer number (175106448).

Almost surely, 2^1221100321 is an apocalyptic number.

It is an amenable number.

1221100321 is a deficient number, since it is larger than the sum of its proper divisors (179751263).

1221100321 is an equidigital number, since it uses as much as digits as its factorization.

1221100321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 663551.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 1221100321 is about 34944.2458925643. The cubic root of 1221100321 is about 1068.8508701529.

Adding to 1221100321 its reverse (1230011221), we get a palindrome (2451111542).

The spelling of 1221100321 in words is "one billion, two hundred twenty-one million, one hundred thousand, three hundred twenty-one".