3996921 has 16 divisors (see below), whose sum is σ = 5702400. Its totient is φ = 2481408.

The previous prime is 3996919. The next prime is 3996931. The reversal of 3996921 is 1296993.

It is a happy number.

It is not a de Polignac number, because 3996921 - 2¹ = 3996919 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 3996921.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3996911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5200 + ... + 5918.

It is an arithmetic number, because the mean of its divisors is an integer number (356400).

Almost surely, 2^3996921 is an apocalyptic number.

It is an amenable number.

3996921 is a deficient number, since it is larger than the sum of its proper divisors (1705479).

3996921 is a wasteful number, since it uses less digits than its factorization.

3996921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 848.

The product of its digits is 26244, while the sum is 39.

The square root of 3996921 is about 1999.2301018142. The cubic root of 3996921 is about 158.6993646764.

The spelling of 3996921 in words is "three million, nine hundred ninety-six thousand, nine hundred twenty-one".