284740021 has 4 divisors (see below), whose sum is σ = 301489452. Its totient is φ = 267990592.

The previous prime is 284740007. The next prime is 284740087. The reversal of 284740021 is 120047482.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120047482 = 2 ⋅60023741.

It can be written as a sum of positive squares in 2 ways, for example, as 205779025 + 78960996 = 14345^2 + 8886^2 .

It is a cyclic number.

It is not a de Polignac number, because 284740021 - 2¹³ = 284731829 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 (284740091) 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, 8374690 + ... + 8374723.

It is an arithmetic number, because the mean of its divisors is an integer number (75372363).

Almost surely, 2^284740021 is an apocalyptic number.

It is an amenable number.

284740021 is a deficient number, since it is larger than the sum of its proper divisors (16749431).

284740021 is a wasteful number, since it uses less digits than its factorization.

284740021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16749430.

The product of its (nonzero) digits is 3584, while the sum is 28.

The square root of 284740021 is about 16874.2413459095. The cubic root of 284740021 is about 657.8842725678.

The spelling of 284740021 in words is "two hundred eighty-four million, seven hundred forty thousand, twenty-one".