11221212511 has 4 divisors (see below), whose sum is σ = 11221805952. Its totient is φ = 11220619072.

The previous prime is 11221212493. The next prime is 11221212521. The reversal of 11221212511 is 11521212211.

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 11221212511 - 2⁵ = 11221212479 is a prime.

It is a super-2 number, since 2×11221212511² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11221212521) 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, 267391 + ... + 306496.

It is an arithmetic number, because the mean of its divisors is an integer number (2805451488).

Almost surely, 2^11221212511 is an apocalyptic number.

11221212511 is a deficient number, since it is larger than the sum of its proper divisors (593441).

11221212511 is an equidigital number, since it uses as much as digits as its factorization.

11221212511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 593440.

The product of its digits is 80, while the sum is 19.

Adding to 11221212511 its reverse (11521212211), we get a palindrome (22742424722).

The spelling of 11221212511 in words is "eleven billion, two hundred twenty-one million, two hundred twelve thousand, five hundred eleven".