11911210921 has 8 divisors (see below), whose sum is σ = 11957750280. Its totient is φ = 11864712192.

The previous prime is 11911210907. The next prime is 11911210957. The reversal of 11911210921 is 12901211911.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 4334378896 + 7576832025 = 65836^2 + 87045^2 .

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 11911210921 - 2¹¹ = 11911208873 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11911210921.

It is not an unprimeable number, because it can be changed into a prime (11911210991) 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, 662985 + ... + 680713.

It is an arithmetic number, because the mean of its divisors is an integer number (1494718785).

Almost surely, 2^11911210921 is an apocalyptic number.

It is an amenable number.

11911210921 is a deficient number, since it is larger than the sum of its proper divisors (46539359).

11911210921 is a wasteful number, since it uses less digits than its factorization.

11911210921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20315.

The product of its (nonzero) digits is 324, while the sum is 28.

The spelling of 11911210921 in words is "eleven billion, nine hundred eleven million, two hundred ten thousand, nine hundred twenty-one".