16687661 has 4 divisors (see below), whose sum is σ = 16746912. Its totient is φ = 16628412.

The previous prime is 16687651. The next prime is 16687667. The reversal of 16687661 is 16678661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16687661 - 2⁶ = 16687597 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 (16687667) 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, 29201 + ... + 29766.

It is an arithmetic number, because the mean of its divisors is an integer number (4186728).

Almost surely, 2^16687661 is an apocalyptic number.

It is an amenable number.

16687661 is a deficient number, since it is larger than the sum of its proper divisors (59251).

16687661 is an equidigital number, since it uses as much as digits as its factorization.

16687661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59250.

The product of its digits is 72576, while the sum is 41.

The square root of 16687661 is about 4085.0533656245. The cubic root of 16687661 is about 255.5436868324.

The spelling of 16687661 in words is "sixteen million, six hundred eighty-seven thousand, six hundred sixty-one".