561272166 has 240 divisors, whose sum is σ = 1627224144. Its totient is φ = 144027072.

The previous prime is 561272161. The next prime is 561272191. The reversal of 561272166 is 661272165.

It is a happy number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 561272166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561272161) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 15169500 + ... + 15169536.

Almost surely, 2^561272166 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 561272166, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (813612072).

561272166 is an abundant number, since it is smaller than the sum of its proper divisors (1065951978).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

561272166 is an equidigital number, since it uses as much as digits as its factorization.

561272166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95 (or 62 counting only the distinct ones).

The product of its digits is 30240, while the sum is 36.

The square root of 561272166 is about 23691.1832967456. The cubic root of 561272166 is about 824.8807497058.

Subtracting 561272166 from its reverse (661272165), we obtain a palindrome (99999999).

The spelling of 561272166 in words is "five hundred sixty-one million, two hundred seventy-two thousand, one hundred sixty-six".