1211920109 has 8 divisors (see below), whose sum is σ = 1224765408. Its totient is φ = 1199091600.

The previous prime is 1211920103. The next prime is 1211920133. The reversal of 1211920109 is 9010291121.

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 1211920109 - 2⁴ = 1211920093 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211920103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 185354 + ... + 191780.

It is an arithmetic number, because the mean of its divisors is an integer number (153095676).

Almost surely, 2^1211920109 is an apocalyptic number.

It is an amenable number.

1211920109 is a deficient number, since it is larger than the sum of its proper divisors (12845299).

1211920109 is a wasteful number, since it uses less digits than its factorization.

1211920109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8395.

The product of its (nonzero) digits is 324, while the sum is 26.

The square root of 1211920109 is about 34812.6429476419. The cubic root of 1211920109 is about 1066.1655952010.

The spelling of 1211920109 in words is "one billion, two hundred eleven million, nine hundred twenty thousand, one hundred nine".