3971689 has 4 divisors (see below), whose sum is σ = 4099840. Its totient is φ = 3843540.

The previous prime is 3971687. The next prime is 3971713. The reversal of 3971689 is 9861793.

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, and also an emirpimes, since its reverse is a distinct semiprime: 9861793 = 401 ⋅24593.

It is a cyclic number.

It is not a de Polignac number, because 3971689 - 2¹ = 3971687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3971687) 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, 64029 + ... + 64090.

It is an arithmetic number, because the mean of its divisors is an integer number (1024960).

Almost surely, 2^3971689 is an apocalyptic number.

It is an amenable number.

3971689 is a deficient number, since it is larger than the sum of its proper divisors (128151).

3971689 is a wasteful number, since it uses less digits than its factorization.

3971689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128150.

The product of its digits is 81648, while the sum is 43.

The square root of 3971689 is about 1992.9096818471. The cubic root of 3971689 is about 158.3647105559.

The spelling of 3971689 in words is "three million, nine hundred seventy-one thousand, six hundred eighty-nine".