11991915 has 32 divisors (see below), whose sum is σ = 22962240. Its totient is φ = 5902848.

The previous prime is 11991913. The next prime is 11991937. The reversal of 11991915 is 51919911.

It is not a de Polignac number, because 11991915 - 2¹ = 11991913 is a prime.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 11991915.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11991911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1662 + ... + 5171.

It is an arithmetic number, because the mean of its divisors is an integer number (717570).

Almost surely, 2^11991915 is an apocalyptic number.

11991915 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

11991915 is a deficient number, since it is larger than the sum of its proper divisors (10970325).

11991915 is a wasteful number, since it uses less digits than its factorization.

11991915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6860 (or 6854 counting only the distinct ones).

The product of its digits is 3645, while the sum is 36.

The square root of 11991915 is about 3462.9344492785. The cubic root of 11991915 is about 228.8914202109.

The spelling of 11991915 in words is "eleven million, nine hundred ninety-one thousand, nine hundred fifteen".