11978987 has 4 divisors (see below), whose sum is σ = 12609480. Its totient is φ = 11348496.

The previous prime is 11978959. The next prime is 11979029. The reversal of 11978987 is 78987911.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78987911 = 23 ⋅3434257.

It is a cyclic number.

It is not a de Polignac number, because 11978987 - 2⁸ = 11978731 is a prime.

It is a super-2 number, since 2×11978987² = 286992259092338, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11978917) 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, 315218 + ... + 315255.

It is an arithmetic number, because the mean of its divisors is an integer number (3152370).

Almost surely, 2^11978987 is an apocalyptic number.

11978987 is a deficient number, since it is larger than the sum of its proper divisors (630493).

11978987 is an equidigital number, since it uses as much as digits as its factorization.

11978987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630492.

The product of its digits is 254016, while the sum is 50.

The square root of 11978987 is about 3461.0673209286. The cubic root of 11978987 is about 228.8091377653.

The spelling of 11978987 in words is "eleven million, nine hundred seventy-eight thousand, nine hundred eighty-seven".