1221311001 has 4 divisors (see below), whose sum is σ = 1628414672. Its totient is φ = 814207332.

The previous prime is 1221310997. The next prime is 1221311057. The reversal of 1221311001 is 1001131221.

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.

It is not a de Polignac number, because 1221311001 - 2² = 1221310997 is a prime.

It is a super-2 number, since 2×1221311001² = 2983201122327244002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221311071) 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, 203551831 + ... + 203551836.

It is an arithmetic number, because the mean of its divisors is an integer number (407103668).

Almost surely, 2^1221311001 is an apocalyptic number.

It is an amenable number.

1221311001 is a deficient number, since it is larger than the sum of its proper divisors (407103671).

1221311001 is an equidigital number, since it uses as much as digits as its factorization.

1221311001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 407103670.

The product of its (nonzero) digits is 12, while the sum is 12.

The square root of 1221311001 is about 34947.2602788831. The cubic root of 1221311001 is about 1068.9123372708.

Adding to 1221311001 its reverse (1001131221), we get a palindrome (2222442222).

The spelling of 1221311001 in words is "one billion, two hundred twenty-one million, three hundred eleven thousand, one".