4021391 has 8 divisors (see below), whose sum is σ = 4405968. Its totient is φ = 3640000.

The previous prime is 4021387. The next prime is 4021397. The reversal of 4021391 is 1931204.

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

It is a cyclic number.

It is not a de Polignac number, because 4021391 - 2² = 4021387 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4021397) 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, 2441 + ... + 3741.

It is an arithmetic number, because the mean of its divisors is an integer number (550746).

Almost surely, 2^4021391 is an apocalyptic number.

4021391 is a deficient number, since it is larger than the sum of its proper divisors (384577).

4021391 is a wasteful number, since it uses less digits than its factorization.

4021391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1593.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 4021391 is about 2005.3406194460. The cubic root of 4021391 is about 159.0225697429.

Adding to 4021391 its reverse (1931204), we get a palindrome (5952595).

It can be divided in two parts, 40213 and 91, that added together give a palindrome (40304).

The spelling of 4021391 in words is "four million, twenty-one thousand, three hundred ninety-one".