616561609 has 4 divisors (see below), whose sum is σ = 649012240. Its totient is φ = 584110980.

The previous prime is 616561607. The next prime is 616561613. The reversal of 616561609 is 906165616.

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 616561609 - 2¹ = 616561607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (616561601) 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, 16225287 + ... + 16225324.

It is an arithmetic number, because the mean of its divisors is an integer number (162253060).

Almost surely, 2^616561609 is an apocalyptic number.

It is an amenable number.

616561609 is a deficient number, since it is larger than the sum of its proper divisors (32450631).

616561609 is a wasteful number, since it uses less digits than its factorization.

616561609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32450630.

The product of its (nonzero) digits is 58320, while the sum is 40.

The square root of 616561609 is about 24830.6586501446. The cubic root of 616561609 is about 851.1226729315.

The spelling of 616561609 in words is "six hundred sixteen million, five hundred sixty-one thousand, six hundred nine".