11173907721 has 4 divisors (see below), whose sum is σ = 14898543632. Its totient is φ = 7449271812.

The previous prime is 11173907711. The next prime is 11173907737. The reversal of 11173907721 is 12770937111.

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 not a de Polignac number, because 11173907721 - 2⁹ = 11173907209 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 11173907721.

It is not an unprimeable number, because it can be changed into a prime (11173907711) 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, 1862317951 + ... + 1862317956.

It is an arithmetic number, because the mean of its divisors is an integer number (3724635908).

Almost surely, 2^11173907721 is an apocalyptic number.

It is an amenable number.

11173907721 is a deficient number, since it is larger than the sum of its proper divisors (3724635911).

11173907721 is an equidigital number, since it uses as much as digits as its factorization.

11173907721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3724635910.

The product of its (nonzero) digits is 18522, while the sum is 39.

It can be divided in two parts, 11173907 and 721, that added together give a triangular number (11174628 = T₄₇₂₇).

The spelling of 11173907721 in words is "eleven billion, one hundred seventy-three million, nine hundred seven thousand, seven hundred twenty-one".