3967021 has 4 divisors (see below), whose sum is σ = 3971200. Its totient is φ = 3962844.

The previous prime is 3966961. The next prime is 3967027. The reversal of 3967021 is 1207693.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1207693 = 191 ⋅6323.

It is a cyclic number.

It is not a de Polignac number, because 3967021 - 2¹¹ = 3964973 is a prime.

It is a super-2 number, since 2×3967021² = 31474511228882, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3967027) 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, 100 + ... + 2818.

It is an arithmetic number, because the mean of its divisors is an integer number (992800).

Almost surely, 2^3967021 is an apocalyptic number.

It is an amenable number.

3967021 is a deficient number, since it is larger than the sum of its proper divisors (4179).

3967021 is a wasteful number, since it uses less digits than its factorization.

3967021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4178.

The product of its (nonzero) digits is 2268, while the sum is 28.

The square root of 3967021 is about 1991.7381856057. The cubic root of 3967021 is about 158.3026432360.

The spelling of 3967021 in words is "three million, nine hundred sixty-seven thousand, twenty-one".