2172840561 has 12 divisors (see below), whose sum is σ = 3239791360. Its totient is φ = 1401832440.

The previous prime is 2172840559. The next prime is 2172840581. The reversal of 2172840561 is 1650482712.

2172840561 is a `hidden beast` number, since 2 + 17 + 2 + 84 + 0 + 561 = 666.

It is not a de Polignac number, because 2172840561 - 2¹ = 2172840559 is a prime.

It is a super-2 number, since 2×2172840561² = 9442472207053589442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2172840581) 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 11 ways as a sum of consecutive naturals, for example, 3893701 + ... + 3894258.

Almost surely, 2^2172840561 is an apocalyptic number.

It is an amenable number.

2172840561 is a deficient number, since it is larger than the sum of its proper divisors (1066950799).

2172840561 is a wasteful number, since it uses less digits than its factorization.

2172840561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7787996 (or 7787993 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The square root of 2172840561 is about 46613.7378998938. The cubic root of 2172840561 is about 1295.2172503146.

The spelling of 2172840561 in words is "two billion, one hundred seventy-two million, eight hundred forty thousand, five hundred sixty-one".