3966921 has 32 divisors (see below), whose sum is σ = 6809600. Its totient is φ = 2235600.

The previous prime is 3966913. The next prime is 3966923. The reversal of 3966921 is 1296693.

It is not a de Polignac number, because 3966921 - 2³ = 3966913 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (3966923) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26196 + ... + 26346.

It is an arithmetic number, because the mean of its divisors is an integer number (212800).

Almost surely, 2^3966921 is an apocalyptic number.

It is an amenable number.

3966921 is a deficient number, since it is larger than the sum of its proper divisors (2842679).

3966921 is a wasteful number, since it uses less digits than its factorization.

3966921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 306 (or 300 counting only the distinct ones).

The product of its digits is 17496, while the sum is 36.

The square root of 3966921 is about 1991.7130817465. The cubic root of 3966921 is about 158.3013130693.

It can be divided in two parts, 396692 and 1, that added together give a palindrome (396693).

The spelling of 3966921 in words is "three million, nine hundred sixty-six thousand, nine hundred twenty-one".