11971915 has 4 divisors (see below), whose sum is σ = 14366304. Its totient is φ = 9577528.

The previous prime is 11971913. The next prime is 11971943. The reversal of 11971915 is 51917911.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 51917911 = 83 ⋅625517.

It is a cyclic number.

It is not a de Polignac number, because 11971915 - 2¹ = 11971913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11971913) 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, 1197187 + ... + 1197196.

It is an arithmetic number, because the mean of its divisors is an integer number (3591576).

Almost surely, 2^11971915 is an apocalyptic number.

11971915 is a deficient number, since it is larger than the sum of its proper divisors (2394389).

11971915 is an equidigital number, since it uses as much as digits as its factorization.

11971915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2394388.

The product of its digits is 2835, while the sum is 34.

The square root of 11971915 is about 3460.0455199318. The cubic root of 11971915 is about 228.7641017713.

The spelling of 11971915 in words is "eleven million, nine hundred seventy-one thousand, nine hundred fifteen".