11721128 has 8 divisors (see below), whose sum is σ = 21977130. Its totient is φ = 5860560.

The previous prime is 11721113. The next prime is 11721139. The reversal of 11721128 is 82112711.

11721128 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 11546404 + 174724 = 3398^2 + 418^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 732563 + ... + 732578.

Almost surely, 2^11721128 is an apocalyptic number.

It is an amenable number.

11721128 is a deficient number, since it is larger than the sum of its proper divisors (10256002).

11721128 is a wasteful number, since it uses less digits than its factorization.

11721128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1465147 (or 1465143 counting only the distinct ones).

The product of its digits is 224, while the sum is 23.

The square root of 11721128 is about 3423.6132959200. The cubic root of 11721128 is about 227.1554370214.

Adding to 11721128 its reverse (82112711), we get a palindrome (93833839).

It can be divided in two parts, 117 and 21128, that multiplied together give a triangular number (2471976 = T₂₂₂₃).

The spelling of 11721128 in words is "eleven million, seven hundred twenty-one thousand, one hundred twenty-eight".