1211209999 has 8 divisors (see below), whose sum is σ = 1291686480. Its totient is φ = 1131758976.

The previous prime is 1211209973. The next prime is 1211210009. The reversal of 1211209999 is 9999021121.

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 1211209999 - 2¹³ = 1211201807 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 (1211209949) 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, 253924 + ... + 258649.

It is an arithmetic number, because the mean of its divisors is an integer number (161460810).

Almost surely, 2^1211209999 is an apocalyptic number.

1211209999 is a deficient number, since it is larger than the sum of its proper divisors (80476481).

1211209999 is a wasteful number, since it uses less digits than its factorization.

1211209999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 512729.

The product of its (nonzero) digits is 26244, while the sum is 43.

The square root of 1211209999 is about 34802.4424286572. The cubic root of 1211209999 is about 1065.9573188843.

The spelling of 1211209999 in words is "one billion, two hundred eleven million, two hundred nine thousand, nine hundred ninety-nine".