3890721 has 4 divisors (see below), whose sum is σ = 5187632. Its totient is φ = 2593812.

The previous prime is 3890713. The next prime is 3890737. The reversal of 3890721 is 1270983.

It is a happy number.

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.

It is not a de Polignac number, because 3890721 - 2³ = 3890713 is a prime.

It is a D-number.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3890701) 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, 648451 + ... + 648456.

It is an arithmetic number, because the mean of its divisors is an integer number (1296908).

Almost surely, 2^3890721 is an apocalyptic number.

It is an amenable number.

3890721 is a deficient number, since it is larger than the sum of its proper divisors (1296911).

3890721 is a wasteful number, since it uses less digits than its factorization.

3890721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1296910.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 3890721 is about 1972.4910646185. The cubic root of 3890721 is about 157.2811573894.

The spelling of 3890721 in words is "three million, eight hundred ninety thousand, seven hundred twenty-one".