609131021 has 4 divisors (see below), whose sum is σ = 609258012. Its totient is φ = 609004032.

The previous prime is 609131009. The next prime is 609131023. The reversal of 609131021 is 120131906.

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 463928521 + 145202500 = 21539^2 + 12050^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-609131021 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 (609131023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56006 + ... + 65991.

It is an arithmetic number, because the mean of its divisors is an integer number (152314503).

Almost surely, 2^609131021 is an apocalyptic number.

It is an amenable number.

609131021 is a deficient number, since it is larger than the sum of its proper divisors (126991).

609131021 is a wasteful number, since it uses less digits than its factorization.

609131021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126990.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 609131021 is about 24680.5798351659. The cubic root of 609131021 is about 847.6896990684.

Adding to 609131021 its reverse (120131906), we get a palindrome (729262927).

The spelling of 609131021 in words is "six hundred nine million, one hundred thirty-one thousand, twenty-one".