3920721 has 8 divisors (see below), whose sum is σ = 5974464. Its totient is φ = 2240400.

The previous prime is 3920689. The next prime is 3920729. The reversal of 3920721 is 1270293.

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

It is not a de Polignac number, because 3920721 - 2⁵ = 3920689 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 3920691 and 3920700.

It is not an unprimeable number, because it can be changed into a prime (3920729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 93330 + ... + 93371.

It is an arithmetic number, because the mean of its divisors is an integer number (746808).

Almost surely, 2^3920721 is an apocalyptic number.

It is an amenable number.

3920721 is a deficient number, since it is larger than the sum of its proper divisors (2053743).

3920721 is a wasteful number, since it uses less digits than its factorization.

3920721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186711.

The product of its (nonzero) digits is 756, while the sum is 24.

The square root of 3920721 is about 1980.0810589468. The cubic root of 3920721 is about 157.6843696305.

The spelling of 3920721 in words is "three million, nine hundred twenty thousand, seven hundred twenty-one".