661028500 has 96 divisors (see below), whose sum is σ = 1626153984. Its totient is φ = 232560000.

The previous prime is 661028497. The next prime is 661028549. The reversal of 661028500 is 5820166.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 168562 + ... + 172438.

It is an arithmetic number, because the mean of its divisors is an integer number (16939104).

Almost surely, 2^661028500 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 661028500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (813076992).

661028500 is an abundant number, since it is smaller than the sum of its proper divisors (965125484).

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

661028500 is a wasteful number, since it uses less digits than its factorization.

661028500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3938 (or 3926 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 661028500 is about 25710.4745191527. The cubic root of 661028500 is about 871.1107932578.

Adding to 661028500 its reverse (5820166), we get a palindrome (666848666).

The spelling of 661028500 in words is "six hundred sixty-one million, twenty-eight thousand, five hundred".