661125200 has 60 divisors (see below), whose sum is σ = 1594056828. Its totient is φ = 263500800.

The previous prime is 661125191. The next prime is 661125239. The reversal of 661125200 is 2521166.

It can be written as a sum of positive squares in 6 ways, for example, as 137264656 + 523860544 = 11716^2 + 22888^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 114380 + ... + 120020.

Almost surely, 2^661125200 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661125200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (797028414).

661125200 is an abundant number, since it is smaller than the sum of its proper divisors (932931628).

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

661125200 is a wasteful number, since it uses less digits than its factorization.

661125200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5952 (or 5941 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 661125200 is about 25712.3550068834. The cubic root of 661125200 is about 871.1532686359.

Adding to 661125200 its reverse (2521166), we get a palindrome (663646366).

The spelling of 661125200 in words is "six hundred sixty-one million, one hundred twenty-five thousand, two hundred".