531609121 has 4 divisors (see below), whose sum is σ = 549940500. Its totient is φ = 513277744.

The previous prime is 531609079. The next prime is 531609139. The reversal of 531609121 is 121906135.

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 197121600 + 334487521 = 14040^2 + 18289^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-531609121 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 531609121.

It is not an unprimeable number, because it can be changed into a prime (531609161) 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, 9165646 + ... + 9165703.

It is an arithmetic number, because the mean of its divisors is an integer number (137485125).

Almost surely, 2^531609121 is an apocalyptic number.

It is an amenable number.

531609121 is a deficient number, since it is larger than the sum of its proper divisors (18331379).

531609121 is a wasteful number, since it uses less digits than its factorization.

531609121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18331378.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 531609121 is about 23056.6502554035. The cubic root of 531609121 is about 810.0854053116.

The spelling of 531609121 in words is "five hundred thirty-one million, six hundred nine thousand, one hundred twenty-one".