1221100999 has 8 divisors (see below), whose sum is σ = 1263780000. Its totient is φ = 1178460192.

The previous prime is 1221100997. The next prime is 1221101017. The reversal of 1221100999 is 9990011221.

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 1221100999 - 2¹ = 1221100997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221100997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 65662 + ... + 82180.

It is an arithmetic number, because the mean of its divisors is an integer number (157972500).

Almost surely, 2^1221100999 is an apocalyptic number.

1221100999 is a deficient number, since it is larger than the sum of its proper divisors (42679001).

1221100999 is a wasteful number, since it uses less digits than its factorization.

1221100999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19097.

The product of its (nonzero) digits is 2916, while the sum is 34.

The square root of 1221100999 is about 34944.2555937310. The cubic root of 1221100999 is about 1068.8510679747.

The spelling of 1221100999 in words is "one billion, two hundred twenty-one million, one hundred thousand, nine hundred ninety-nine".