11651228821 has 4 divisors (see below), whose sum is σ = 12027074944. Its totient is φ = 11275382700.

The previous prime is 11651228807. The next prime is 11651228837. The reversal of 11651228821 is 12882215611.

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 not a de Polignac number, because 11651228821 - 2¹¹ = 11651226773 is a prime.

It is a super-2 number, since 2×11651228821² (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 (11651228891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 187923015 + ... + 187923076.

It is an arithmetic number, because the mean of its divisors is an integer number (3006768736).

Almost surely, 2^11651228821 is an apocalyptic number.

It is an amenable number.

11651228821 is a deficient number, since it is larger than the sum of its proper divisors (375846123).

11651228821 is an equidigital number, since it uses as much as digits as its factorization.

11651228821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375846122.

The product of its digits is 15360, while the sum is 37.

The spelling of 11651228821 in words is "eleven billion, six hundred fifty-one million, two hundred twenty-eight thousand, eight hundred twenty-one".