3993621 has 4 divisors (see below), whose sum is σ = 5324832. Its totient is φ = 2662412.

The previous prime is 3993617. The next prime is 3993631. The reversal of 3993621 is 1263993.

3993621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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: 1263993 = 3 ⋅421331.

It is a cyclic number.

It is not a de Polignac number, because 3993621 - 2² = 3993617 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3993601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 665601 + ... + 665606.

It is an arithmetic number, because the mean of its divisors is an integer number (1331208).

Almost surely, 2^3993621 is an apocalyptic number.

It is an amenable number.

3993621 is a deficient number, since it is larger than the sum of its proper divisors (1331211).

3993621 is a wasteful number, since it uses less digits than its factorization.

3993621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1331210.

The product of its digits is 8748, while the sum is 33.

The square root of 3993621 is about 1998.4046136856. The cubic root of 3993621 is about 158.6556767059.

The spelling of 3993621 in words is "three million, nine hundred ninety-three thousand, six hundred twenty-one".