16991071 has 4 divisors (see below), whose sum is σ = 17577000. Its totient is φ = 16405144.

The previous prime is 16991057. The next prime is 16991099. The reversal of 16991071 is 17019961.

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 16991071 - 2⁹ = 16990559 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 (16991021) 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, 292921 + ... + 292978.

It is an arithmetic number, because the mean of its divisors is an integer number (4394250).

Almost surely, 2^16991071 is an apocalyptic number.

16991071 is a deficient number, since it is larger than the sum of its proper divisors (585929).

16991071 is an equidigital number, since it uses as much as digits as its factorization.

16991071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 585928.

The product of its (nonzero) digits is 3402, while the sum is 34.

The square root of 16991071 is about 4122.0226831011. The cubic root of 16991071 is about 257.0831335872.

The spelling of 16991071 in words is "sixteen million, nine hundred ninety-one thousand, seventy-one".