509398621 has 4 divisors (see below), whose sum is σ = 509795100. Its totient is φ = 509002144.

The previous prime is 509398579. The next prime is 509398657. The reversal of 509398621 is 126893905.

It is a happy number.

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 357739396 + 151659225 = 18914^2 + 12315^2 .

It is a cyclic number.

It is not a de Polignac number, because 509398621 - 2¹³ = 509390429 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 (509398691) 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, 196306 + ... + 198883.

It is an arithmetic number, because the mean of its divisors is an integer number (127448775).

Almost surely, 2^509398621 is an apocalyptic number.

It is an amenable number.

509398621 is a deficient number, since it is larger than the sum of its proper divisors (396479).

509398621 is a wasteful number, since it uses less digits than its factorization.

509398621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396478.

The product of its (nonzero) digits is 116640, while the sum is 43.

The square root of 509398621 is about 22569.8608989954. The cubic root of 509398621 is about 798.6428139638.

The spelling of 509398621 in words is "five hundred nine million, three hundred ninety-eight thousand, six hundred twenty-one".