509539981 has 4 divisors (see below), whose sum is σ = 521389792. Its totient is φ = 497690172.

The previous prime is 509539973. The next prime is 509539991. The reversal of 509539981 is 189935905.

It is a happy number.

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 509539981 - 2³ = 509539973 is a prime.

It is a super-2 number, since 2×509539981² = 519261984474960722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (509539931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5924841 + ... + 5924926.

It is an arithmetic number, because the mean of its divisors is an integer number (130347448).

Almost surely, 2^509539981 is an apocalyptic number.

It is an amenable number.

509539981 is a deficient number, since it is larger than the sum of its proper divisors (11849811).

509539981 is a wasteful number, since it uses less digits than its factorization.

509539981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11849810.

The product of its (nonzero) digits is 437400, while the sum is 49.

The square root of 509539981 is about 22572.9922916746. The cubic root of 509539981 is about 798.7166825754.

The spelling of 509539981 in words is "five hundred nine million, five hundred thirty-nine thousand, nine hundred eighty-one".