3957221 has 4 divisors (see below), whose sum is σ = 4016352. Its totient is φ = 3898092.

The previous prime is 3957179. The next prime is 3957223. The reversal of 3957221 is 1227593.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1227593 = 47 ⋅26119.

It is a cyclic number.

It is not a de Polignac number, because 3957221 - 2¹⁴ = 3940837 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 (3957223) 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, 29465 + ... + 29598.

It is an arithmetic number, because the mean of its divisors is an integer number (1004088).

Almost surely, 2^3957221 is an apocalyptic number.

It is an amenable number.

3957221 is a deficient number, since it is larger than the sum of its proper divisors (59131).

3957221 is an equidigital number, since it uses as much as digits as its factorization.

3957221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59130.

The product of its digits is 3780, while the sum is 29.

The square root of 3957221 is about 1989.2765016458. The cubic root of 3957221 is about 158.1721805083.

It can be divided in two parts, 39572 and 21, that added together give a palindrome (39593).

The spelling of 3957221 in words is "three million, nine hundred fifty-seven thousand, two hundred twenty-one".