561505100 has 144 divisors (see below), whose sum is σ = 1399910400. Its totient is φ = 193777920.

The previous prime is 561505097. The next prime is 561505117. The reversal of 561505100 is 1505165.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3136811 + ... + 3136989.

It is an arithmetic number, because the mean of its divisors is an integer number (9721600).

Almost surely, 2^561505100 is an apocalyptic number.

561505100 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 561505100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (699955200).

561505100 is an abundant number, since it is smaller than the sum of its proper divisors (838405300).

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

561505100 is a wasteful number, since it uses less digits than its factorization.

561505100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 352 (or 345 counting only the distinct ones).

The product of its (nonzero) digits is 750, while the sum is 23.

The square root of 561505100 is about 23696.0988350403. The cubic root of 561505100 is about 824.9948453917.

The spelling of 561505100 in words is "five hundred sixty-one million, five hundred five thousand, one hundred".