11989521 has 6 divisors (see below), whose sum is σ = 17318210. Its totient is φ = 7993008.

The previous prime is 11989519. The next prime is 11989531. The reversal of 11989521 is 12598911.

11989521 is digitally balanced in base 2 and base 4, because in such bases 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., 9217296 + 2772225 = 3036^2 + 1665^2 .

It is not a de Polignac number, because 11989521 - 2¹ = 11989519 is a prime.

It is a super-2 number, since 2×11989521² = 287497227618882, which 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 (11989511) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 666076 + ... + 666093.

Almost surely, 2^11989521 is an apocalyptic number.

It is an amenable number.

11989521 is a deficient number, since it is larger than the sum of its proper divisors (5328689).

11989521 is a wasteful number, since it uses less digits than its factorization.

11989521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1332175 (or 1332172 counting only the distinct ones).

The product of its digits is 6480, while the sum is 36.

The square root of 11989521 is about 3462.5887714252. The cubic root of 11989521 is about 228.8761876555.

The spelling of 11989521 in words is "eleven million, nine hundred eighty-nine thousand, five hundred twenty-one".