11187666971209 has 9 divisors (see below), whose sum is σ = 11211804730413. Its totient is φ = 11163581088012.

The previous prime is 11187666971183. The next prime is 11187666971267. The reversal of 11187666971209 is 90217966678111.

It is a happy number.

The square root of 11187666971209 is 3344797.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 11187666971209 - 2³¹ = 11185519487561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11187666975209) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1669050352 + ... + 1669057054.

It is an arithmetic number, because the mean of its divisors is an integer number (1245756081157).

Almost surely, 2^{11187666971209} is an apocalyptic number.

11187666971209 is the 3344797-th square number.

11187666971209 is the 1672399-th centered octagonal number.

It is an amenable number.

11187666971209 is a deficient number, since it is larger than the sum of its proper divisors (24137759204).

11187666971209 is an frugal number, since it uses more digits than its factorization.

11187666971209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14404 (or 7202 counting only the distinct ones).

The product of its (nonzero) digits is 13716864, while the sum is 64.

Multiplying 11187666971209 by its sum of digits (64), we get a square (716010686157376 = 26758376²).

The spelling of 11187666971209 in words is "eleven trillion, one hundred eighty-seven billion, six hundred sixty-six million, nine hundred seventy-one thousand, two hundred nine".