521284009 has 4 divisors (see below), whose sum is σ = 535372804. Its totient is φ = 507195216.

The previous prime is 521283989. The next prime is 521284031. The reversal of 521284009 is 900482125.

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 255104784 + 266179225 = 15972^2 + 16315^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-521284009 is a prime.

It is a super-2 number, since 2×521284009² = 543474036078224162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521284109) 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, 7044342 + ... + 7044415.

It is an arithmetic number, because the mean of its divisors is an integer number (133843201).

Almost surely, 2^521284009 is an apocalyptic number.

It is an amenable number.

521284009 is a deficient number, since it is larger than the sum of its proper divisors (14088795).

521284009 is a wasteful number, since it uses less digits than its factorization.

521284009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14088794.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 521284009 is about 22831.6449035106. The cubic root of 521284009 is about 804.8064856401.

It can be divided in two parts, 52128400 and 9, that multiplied together give a square (469155600 = 21660²).

The spelling of 521284009 in words is "five hundred twenty-one million, two hundred eighty-four thousand, nine".