16571987 has 4 divisors (see below), whose sum is σ = 16884720. Its totient is φ = 16259256.

The previous prime is 16571977. The next prime is 16571993. The reversal of 16571987 is 78917561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78917561 = 239 ⋅330199.

It is a cyclic number.

It is not a de Polignac number, because 16571987 - 2¹⁰ = 16570963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16571927) 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, 156287 + ... + 156392.

It is an arithmetic number, because the mean of its divisors is an integer number (4221180).

Almost surely, 2^16571987 is an apocalyptic number.

16571987 is a deficient number, since it is larger than the sum of its proper divisors (312733).

16571987 is an equidigital number, since it uses as much as digits as its factorization.

16571987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 312732.

The product of its digits is 105840, while the sum is 44.

The square root of 16571987 is about 4070.8705457187. The cubic root of 16571987 is about 254.9518658346.

The spelling of 16571987 in words is "sixteen million, five hundred seventy-one thousand, nine hundred eighty-seven".