4221921 has 16 divisors (see below), whose sum is σ = 6340608. Its totient is φ = 2475600.

The previous prime is 4221913. The next prime is 4221923. The reversal of 4221921 is 1291224.

It is not a de Polignac number, because 4221921 - 2³ = 4221913 is a prime.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (4221923) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1041 + ... + 3086.

It is an arithmetic number, because the mean of its divisors is an integer number (396288).

Almost surely, 2^4221921 is an apocalyptic number.

It is an amenable number.

4221921 is a deficient number, since it is larger than the sum of its proper divisors (2118687).

4221921 is a wasteful number, since it uses less digits than its factorization.

4221921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4172.

The product of its digits is 288, while the sum is 21.

The square root of 4221921 is about 2054.7313693035. The cubic root of 4221921 is about 161.6230758350.

The spelling of 4221921 in words is "four million, two hundred twenty-one thousand, nine hundred twenty-one".