3891987 has 12 divisors (see below), whose sum is σ = 6132984. Its totient is φ = 2358720.

The previous prime is 3891977. The next prime is 3892001. The reversal of 3891987 is 7891983.

It is not a de Polignac number, because 3891987 - 2⁴ = 3891971 is a prime.

It is not an unprimeable number, because it can be changed into a prime (3891907) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19558 + ... + 19755.

It is an arithmetic number, because the mean of its divisors is an integer number (511082).

Almost surely, 2^3891987 is an apocalyptic number.

3891987 is a deficient number, since it is larger than the sum of its proper divisors (2240997).

3891987 is a wasteful number, since it uses less digits than its factorization.

3891987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39330 (or 39327 counting only the distinct ones).

The product of its digits is 108864, while the sum is 45.

The square root of 3891987 is about 1972.8119525185. The cubic root of 3891987 is about 157.2982147550.

The spelling of 3891987 in words is "three million, eight hundred ninety-one thousand, nine hundred eighty-seven".