4221640 has 16 divisors (see below), whose sum is σ = 9498780. Its totient is φ = 1688640.

The previous prime is 4221631. The next prime is 4221641. The reversal of 4221640 is 461224.

It can be written as a sum of positive squares in 2 ways, for example, as 4104676 + 116964 = 2026^2 + 342^2 .

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (4221641) 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, 52731 + ... + 52810.

Almost surely, 2^4221640 is an apocalyptic number.

4221640 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

4221640 is an abundant number, since it is smaller than the sum of its proper divisors (5277140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

4221640 is a wasteful number, since it uses less digits than its factorization.

4221640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105552 (or 105548 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 4221640 is about 2054.6629893975. The cubic root of 4221640 is about 161.6194900193.

Adding to 4221640 its reverse (461224), we get a palindrome (4682864).

The spelling of 4221640 in words is "four million, two hundred twenty-one thousand, six hundred forty".