428728261 has 4 divisors (see below), whose sum is σ = 461707372. Its totient is φ = 395749152.

The previous prime is 428728259. The next prime is 428728271. The reversal of 428728261 is 162827824.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 143760100 + 284968161 = 11990^2 + 16881^2 .

It is a cyclic number.

It is not a de Polignac number, because 428728261 - 2¹ = 428728259 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (428728231) 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, 16489536 + ... + 16489561.

It is an arithmetic number, because the mean of its divisors is an integer number (115426843).

Almost surely, 2^428728261 is an apocalyptic number.

It is an amenable number.

428728261 is a deficient number, since it is larger than the sum of its proper divisors (32979111).

428728261 is a wasteful number, since it uses less digits than its factorization.

428728261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32979110.

The product of its digits is 86016, while the sum is 40.

The square root of 428728261 is about 20705.7542968132. The cubic root of 428728261 is about 754.0393970085.

The spelling of 428728261 in words is "four hundred twenty-eight million, seven hundred twenty-eight thousand, two hundred sixty-one".