16631971 has 4 divisors (see below), whose sum is σ = 16641000. Its totient is φ = 16622944.

The previous prime is 16631959. The next prime is 16631977. The reversal of 16631971 is 17913661.

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: 17913661 = 37 ⋅484153.

It is a cyclic number.

It is not a de Polignac number, because 16631971 - 2⁵ = 16631939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16631977) 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, 646 + ... + 5803.

It is an arithmetic number, because the mean of its divisors is an integer number (4160250).

Almost surely, 2^16631971 is an apocalyptic number.

16631971 is a deficient number, since it is larger than the sum of its proper divisors (9029).

16631971 is an equidigital number, since it uses as much as digits as its factorization.

16631971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9028.

The product of its digits is 6804, while the sum is 34.

The square root of 16631971 is about 4078.2313568507. The cubic root of 16631971 is about 255.2591035479.

The spelling of 16631971 in words is "sixteen million, six hundred thirty-one thousand, nine hundred seventy-one".