561649955 has 24 divisors (see below), whose sum is σ = 693226512. Its totient is φ = 436794624.

The previous prime is 561649943. The next prime is 561649993. The reversal of 561649955 is 559946165.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-561649955 is a prime.

It is a Smith number, since the sum of its digits (50) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 2850917 + ... + 2851113.

It is an arithmetic number, because the mean of its divisors is an integer number (28884438).

Almost surely, 2^561649955 is an apocalyptic number.

561649955 is a deficient number, since it is larger than the sum of its proper divisors (131576557).

561649955 is a wasteful number, since it uses less digits than its factorization.

561649955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 455 (or 382 counting only the distinct ones).

The product of its digits is 1458000, while the sum is 50.

The square root of 561649955 is about 23699.1551537180. The cubic root of 561649955 is about 825.0657823273.

The spelling of 561649955 in words is "five hundred sixty-one million, six hundred forty-nine thousand, nine hundred fifty-five".