4221639 has 14 divisors (see below), whose sum is σ = 6330656. Its totient is φ = 2813940.

The previous prime is 4221631. The next prime is 4221641. The reversal of 4221639 is 9361224.

4221639 is a `hidden beast` number, since 4 + 2 + 21 + 639 = 666.

It is not a de Polignac number, because 4221639 - 2³ = 4221631 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4221631) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 2167 + ... + 3624.

Almost surely, 2^4221639 is an apocalyptic number.

4221639 is a deficient number, since it is larger than the sum of its proper divisors (2109017).

4221639 is an frugal number, since it uses more digits than its factorization.

4221639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5809 (or 5794 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 4221639 is about 2054.6627460486. The cubic root of 4221639 is about 161.6194772581.

The spelling of 4221639 in words is "four million, two hundred twenty-one thousand, six hundred thirty-nine".