11971951 has 4 divisors (see below), whose sum is σ = 11979952. Its totient is φ = 11963952.

The previous prime is 11971943. The next prime is 11971987. The reversal of 11971951 is 15917911.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 15917911 = 31 ⋅513481.

It is a cyclic number.

It is not a de Polignac number, because 11971951 - 2³ = 11971943 is a prime.

It is a super-3 number, since 3×11971951³ (a number of 22 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11971901) 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, 1011 + ... + 4996.

It is an arithmetic number, because the mean of its divisors is an integer number (2994988).

Almost surely, 2^11971951 is an apocalyptic number.

11971951 is a deficient number, since it is larger than the sum of its proper divisors (8001).

11971951 is an equidigital number, since it uses as much as digits as its factorization.

11971951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8000.

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

The square root of 11971951 is about 3460.0507221716. The cubic root of 11971951 is about 228.7643310718.

The spelling of 11971951 in words is "eleven million, nine hundred seventy-one thousand, nine hundred fifty-one".