1221010999 has 4 divisors (see below), whose sum is σ = 1314934936. Its totient is φ = 1127087064.

The previous prime is 1221010997. The next prime is 1221011021. The reversal of 1221010999 is 9990101221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221010999 - 2¹ = 1221010997 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 (1221010997) 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, 46961949 + ... + 46961974.

It is an arithmetic number, because the mean of its divisors is an integer number (328733734).

Almost surely, 2^1221010999 is an apocalyptic number.

1221010999 is a deficient number, since it is larger than the sum of its proper divisors (93923937).

1221010999 is an equidigital number, since it uses as much as digits as its factorization.

1221010999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93923936.

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

The square root of 1221010999 is about 34942.9678046957. The cubic root of 1221010999 is about 1068.8248078047.

The spelling of 1221010999 in words is "one billion, two hundred twenty-one million, ten thousand, nine hundred ninety-nine".