11971919 has 4 divisors (see below), whose sum is σ = 12602040. Its totient is φ = 11341800.

The previous prime is 11971913. The next prime is 11971943. The reversal of 11971919 is 91917911.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 91917911 = 61 ⋅1506851.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11971919 is a prime.

It is a super-2 number, since 2×11971919² = 286653689085122, which contains 22 as substring.

It is a Duffinian number.

11971919 is a modest number, since divided by 1919 gives 1197 as remainder.

It is a congruent 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, 315032 + ... + 315069.

It is an arithmetic number, because the mean of its divisors is an integer number (3150510).

Almost surely, 2^11971919 is an apocalyptic number.

11971919 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

11971919 is a deficient number, since it is larger than the sum of its proper divisors (630121).

11971919 is an equidigital number, since it uses as much as digits as its factorization.

11971919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 630120.

The product of its digits is 5103, while the sum is 38.

The square root of 11971919 is about 3460.0460979588. The cubic root of 11971919 is about 228.7641272492.

The spelling of 11971919 in words is "eleven million, nine hundred seventy-one thousand, nine hundred nineteen".