11991947 has 24 divisors (see below), whose sum is σ = 14300160. Its totient is φ = 10018800.

The previous prime is 11991943. The next prime is 11991977. The reversal of 11991947 is 74919911.

It is not a de Polignac number, because 11991947 - 2² = 11991943 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11991943) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 86204 + ... + 86342.

It is an arithmetic number, because the mean of its divisors is an integer number (595840).

Almost surely, 2^11991947 is an apocalyptic number.

11991947 is a deficient number, since it is larger than the sum of its proper divisors (2308213).

11991947 is a wasteful number, since it uses less digits than its factorization.

11991947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215 (or 204 counting only the distinct ones).

The product of its digits is 20412, while the sum is 41.

The square root of 11991947 is about 3462.9390696343. The cubic root of 11991947 is about 228.8916238070.

The spelling of 11991947 in words is "eleven million, nine hundred ninety-one thousand, nine hundred forty-seven".