561642643 has 8 divisors (see below), whose sum is σ = 573315408. Its totient is φ = 550009824.

The previous prime is 561642637. The next prime is 561642661. The reversal of 561642643 is 346246165.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 561642643 - 2⁹ = 561642131 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (561642673) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19305 + ... + 38677.

It is an arithmetic number, because the mean of its divisors is an integer number (71664426).

Almost surely, 2^561642643 is an apocalyptic number.

561642643 is a gapful number since it is divisible by the number (53) formed by its first and last digit.

561642643 is a deficient number, since it is larger than the sum of its proper divisors (11672765).

561642643 is a wasteful number, since it uses less digits than its factorization.

561642643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19973.

The product of its digits is 103680, while the sum is 37.

The square root of 561642643 is about 23699.0008861133. Note that the first 3 decimals coincide. The cubic root of 561642643 is about 825.0622018605.

It can be divided in two parts, 561 and 642643, that added together give a square (643204 = 802²).

The spelling of 561642643 in words is "five hundred sixty-one million, six hundred forty-two thousand, six hundred forty-three".