3967721 has 8 divisors (see below), whose sum is σ = 4128000. Its totient is φ = 3809520.

The previous prime is 3967699. The next prime is 3967727. The reversal of 3967721 is 1277693.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3967721 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3967727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4190 + ... + 5048.

It is an arithmetic number, because the mean of its divisors is an integer number (516000).

Almost surely, 2^3967721 is an apocalyptic number.

3967721 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

It is an amenable number.

3967721 is a deficient number, since it is larger than the sum of its proper divisors (160279).

3967721 is a wasteful number, since it uses less digits than its factorization.

3967721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1039.

The product of its digits is 15876, while the sum is 35.

The square root of 3967721 is about 1991.9139037619. The cubic root of 3967721 is about 158.3119537769.

The spelling of 3967721 in words is "three million, nine hundred sixty-seven thousand, seven hundred twenty-one".