561637066 has 4 divisors (see below), whose sum is σ = 842455602. Its totient is φ = 280818532.

The previous prime is 561637039. The next prime is 561637073. The reversal of 561637066 is 660736165.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 561453025 + 184041 = 23695^2 + 429^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140409265 + ... + 140409268.

Almost surely, 2^561637066 is an apocalyptic number.

561637066 is a deficient number, since it is larger than the sum of its proper divisors (280818536).

561637066 is a wasteful number, since it uses less digits than its factorization.

561637066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280818535.

The product of its (nonzero) digits is 136080, while the sum is 40.

The square root of 561637066 is about 23698.8832226331. The cubic root of 561637066 is about 825.0594709501.

Subtracting 561637066 from its reverse (660736165), we obtain a palindrome (99099099).

The spelling of 561637066 in words is "five hundred sixty-one million, six hundred thirty-seven thousand, sixty-six".