1221111001 has 8 divisors (see below), whose sum is σ = 1338885504. Its totient is φ = 1104463920.

The previous prime is 1221110983. The next prime is 1221111007. The reversal of 1221111001 is 1001111221.

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 1221111001 - 2⁹ = 1221110489 is a prime.

It is a super-2 number, since 2×1221111001² = 2982224153526444002, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1221111007) 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, 279585 + ... + 283918.

It is an arithmetic number, because the mean of its divisors is an integer number (167360688).

Almost surely, 2^1221111001 is an apocalyptic number.

1221111001 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221111001 is a deficient number, since it is larger than the sum of its proper divisors (117774503).

1221111001 is a wasteful number, since it uses less digits than its factorization.

1221111001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 563711.

The product of its (nonzero) digits is 4, while the sum is 10.

The square root of 1221111001 is about 34944.3987070890. The cubic root of 1221111001 is about 1068.8539862753.

Adding to 1221111001 its reverse (1001111221), we get a palindrome (2222222222).

The spelling of 1221111001 in words is "one billion, two hundred twenty-one million, one hundred eleven thousand, one".