4281521221 has 4 divisors (see below), whose sum is σ = 4286801344. Its totient is φ = 4276241100.

The previous prime is 4281521191. The next prime is 4281521243. The reversal of 4281521221 is 1221251824.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4281521221 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 4281521221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4281521261) 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, 2638845 + ... + 2640466.

It is an arithmetic number, because the mean of its divisors is an integer number (1071700336).

Almost surely, 2^4281521221 is an apocalyptic number.

It is an amenable number.

4281521221 is a deficient number, since it is larger than the sum of its proper divisors (5280123).

4281521221 is an equidigital number, since it uses as much as digits as its factorization.

4281521221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5280122.

The product of its digits is 2560, while the sum is 28.

The square root of 4281521221 is about 65433.3341730345. The cubic root of 4281521221 is about 1623.8006103182.

The spelling of 4281521221 in words is "four billion, two hundred eighty-one million, five hundred twenty-one thousand, two hundred twenty-one".