11221521521 has 4 divisors (see below), whose sum is σ = 12824596032. Its totient is φ = 9618447012.

The previous prime is 11221521469. The next prime is 11221521541. The reversal of 11221521521 is 12512512211.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11221521521 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (11221521541) 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, 801537245 + ... + 801537258.

It is an arithmetic number, because the mean of its divisors is an integer number (3206149008).

Almost surely, 2^11221521521 is an apocalyptic number.

It is an amenable number.

11221521521 is a deficient number, since it is larger than the sum of its proper divisors (1603074511).

11221521521 is an equidigital number, since it uses as much as digits as its factorization.

11221521521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1603074510.

The product of its digits is 400, while the sum is 23.

The spelling of 11221521521 in words is "eleven billion, two hundred twenty-one million, five hundred twenty-one thousand, five hundred twenty-one".