661103800 has 96 divisors (see below), whose sum is σ = 1761851520. Its totient is φ = 225993600.

The previous prime is 661103783. The next prime is 661103809. The reversal of 661103800 is 8301166.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661103809) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 798987 + ... + 799813.

It is an arithmetic number, because the mean of its divisors is an integer number (18352620).

Almost surely, 2^661103800 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 661103800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (880925760).

661103800 is an abundant number, since it is smaller than the sum of its proper divisors (1100747720).

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

661103800 is a wasteful number, since it uses less digits than its factorization.

661103800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1421 (or 1412 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 661103800 is about 25711.9388611594. The cubic root of 661103800 is about 871.1438690643.

Adding to 661103800 its reverse (8301166), we get a palindrome (669404966).

The spelling of 661103800 in words is "six hundred sixty-one million, one hundred three thousand, eight hundred".