16001691 has 4 divisors (see below), whose sum is σ = 21335592. Its totient is φ = 10667792.

The previous prime is 16001683. The next prime is 16001693. The reversal of 16001691 is 19610061.

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 16001691 - 2³ = 16001683 is a prime.

It is a super-2 number, since 2×16001691² = 512108229718962, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (16001693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2666946 + ... + 2666951.

It is an arithmetic number, because the mean of its divisors is an integer number (5333898).

Almost surely, 2^16001691 is an apocalyptic number.

16001691 is a deficient number, since it is larger than the sum of its proper divisors (5333901).

16001691 is an equidigital number, since it uses as much as digits as its factorization.

16001691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5333900.

The product of its (nonzero) digits is 324, while the sum is 24.

The square root of 16001691 is about 4000.2113694154. The cubic root of 16001691 is about 251.9930868600.

The spelling of 16001691 in words is "sixteen million, one thousand, six hundred ninety-one".