428923221 has 4 divisors (see below), whose sum is σ = 571897632. Its totient is φ = 285948812.

The previous prime is 428923211. The next prime is 428923241. The reversal of 428923221 is 122329824.

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 not a de Polignac number, because 428923221 - 2⁵ = 428923189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (428923211) 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, 71487201 + ... + 71487206.

It is an arithmetic number, because the mean of its divisors is an integer number (142974408).

Almost surely, 2^428923221 is an apocalyptic number.

It is an amenable number.

428923221 is a deficient number, since it is larger than the sum of its proper divisors (142974411).

428923221 is a wasteful number, since it uses less digits than its factorization.

428923221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142974410.

The product of its digits is 13824, while the sum is 33.

The square root of 428923221 is about 20710.4616317454. The cubic root of 428923221 is about 754.1536770443.

The spelling of 428923221 in words is "four hundred twenty-eight million, nine hundred twenty-three thousand, two hundred twenty-one".