665025100 has 72 divisors (see below), whose sum is σ = 1527870960. Its totient is φ = 250817280.

The previous prime is 665025047. The next prime is 665025103. The reversal of 665025100 is 1520566.

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

It is not an unprimeable number, because it can be changed into a prime (665025103) 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, 122034 + ... + 127366.

It is an arithmetic number, because the mean of its divisors is an integer number (21220430).

Almost surely, 2^665025100 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 665025100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (763935480).

665025100 is an abundant number, since it is smaller than the sum of its proper divisors (862845860).

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

665025100 is a wasteful number, since it uses less digits than its factorization.

665025100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5419 (or 5412 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 665025100 is about 25788.0805799889. The cubic root of 665025100 is about 872.8628551258.

Adding to 665025100 its reverse (1520566), we get a palindrome (666545666).

The spelling of 665025100 in words is "six hundred sixty-five million, twenty-five thousand, one hundred".