2108399561 has 4 divisors (see below), whose sum is σ = 2122362624. Its totient is φ = 2094436500.

The previous prime is 2108399507. The next prime is 2108399569. The reversal of 2108399561 is 1659938012.

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 2108399561 - 2¹⁴ = 2108383177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2108399569) 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, 6981305 + ... + 6981606.

It is an arithmetic number, because the mean of its divisors is an integer number (530590656).

Almost surely, 2^2108399561 is an apocalyptic number.

It is an amenable number.

2108399561 is a deficient number, since it is larger than the sum of its proper divisors (13963063).

2108399561 is a wasteful number, since it uses less digits than its factorization.

2108399561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13963062.

The product of its (nonzero) digits is 116640, while the sum is 44.

The square root of 2108399561 is about 45917.3122144578. The cubic root of 2108399561 is about 1282.2842433377.

The spelling of 2108399561 in words is "two billion, one hundred eight million, three hundred ninety-nine thousand, five hundred sixty-one".