16681631 has 4 divisors (see below), whose sum is σ = 16693512. Its totient is φ = 16669752.

The previous prime is 16681597. The next prime is 16681633. The reversal of 16681631 is 13618661.

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 16681631 - 2¹⁰ = 16680607 is a prime.

It is a super-3 number, since 3×16681631³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16681633) 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, 3500 + ... + 6753.

It is an arithmetic number, because the mean of its divisors is an integer number (4173378).

Almost surely, 2^16681631 is an apocalyptic number.

16681631 is a deficient number, since it is larger than the sum of its proper divisors (11881).

16681631 is a wasteful number, since it uses less digits than its factorization.

16681631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11880.

The product of its digits is 5184, while the sum is 32.

The square root of 16681631 is about 4084.3152424856. The cubic root of 16681631 is about 255.5129033277.

The spelling of 16681631 in words is "sixteen million, six hundred eighty-one thousand, six hundred thirty-one".