3921647 has 4 divisors (see below), whose sum is σ = 3925800. Its totient is φ = 3917496.

The previous prime is 3921637. The next prime is 3921649. The reversal of 3921647 is 7461293.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 7461293 = 7 ⋅1065899.

It is a cyclic number.

It is not a de Polignac number, because 3921647 - 2¹⁴ = 3905263 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 (3921649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104 + ... + 2802.

It is an arithmetic number, because the mean of its divisors is an integer number (981450).

Almost surely, 2^3921647 is an apocalyptic number.

3921647 is a deficient number, since it is larger than the sum of its proper divisors (4153).

3921647 is a wasteful number, since it uses less digits than its factorization.

3921647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4152.

The product of its digits is 9072, while the sum is 32.

The square root of 3921647 is about 1980.3148739531. The cubic root of 3921647 is about 157.6967826732.

The spelling of 3921647 in words is "three million, nine hundred twenty-one thousand, six hundred forty-seven".