16347991 has 4 divisors (see below), whose sum is σ = 17834184. Its totient is φ = 14861800.

The previous prime is 16347983. The next prime is 16347997. The reversal of 16347991 is 19974361.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 16347991 - 2³ = 16347983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16347997) 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, 743080 + ... + 743101.

It is an arithmetic number, because the mean of its divisors is an integer number (4458546).

Almost surely, 2^16347991 is an apocalyptic number.

16347991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

16347991 is a deficient number, since it is larger than the sum of its proper divisors (1486193).

16347991 is a wasteful number, since it uses less digits than its factorization.

16347991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1486192.

The product of its digits is 40824, while the sum is 40.

The square root of 16347991 is about 4043.2648936225. The cubic root of 16347991 is about 253.7979617657.

The spelling of 16347991 in words is "sixteen million, three hundred forty-seven thousand, nine hundred ninety-one".