3923721 has 24 divisors (see below), whose sum is σ = 5989984. Its totient is φ = 2566080.

The previous prime is 3923687. The next prime is 3923723. The reversal of 3923721 is 1273293.

3923721 = T₄₆ + T₄₇ + ... + T₂₈₆.

It is a de Polignac number, because none of the positive numbers 2^k-3923721 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3923723) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16161 + ... + 16401.

Almost surely, 2^3923721 is an apocalyptic number.

It is an amenable number.

3923721 is a deficient number, since it is larger than the sum of its proper divisors (2066263).

3923721 is an equidigital number, since it uses as much as digits as its factorization.

3923721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323 (or 311 counting only the distinct ones).

The product of its digits is 2268, while the sum is 27.

The square root of 3923721 is about 1980.8384588350. The cubic root of 3923721 is about 157.7245775842.

The spelling of 3923721 in words is "three million, nine hundred twenty-three thousand, seven hundred twenty-one".