665541220 has 24 divisors (see below), whose sum is σ = 1417324608. Its totient is φ = 262466400.

The previous prime is 665541203. The next prime is 665541221. The reversal of 665541220 is 22145566.

It is not an unprimeable number, because it can be changed into a prime (665541221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 232926 + ... + 235765.

It is an arithmetic number, because the mean of its divisors is an integer number (59055192).

Almost surely, 2^665541220 is an apocalyptic number.

It is an amenable number.

665541220 is an abundant number, since it is smaller than the sum of its proper divisors (751783388).

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

665541220 is a wasteful number, since it uses less digits than its factorization.

665541220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 468771 (or 468769 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 31.

The square root of 665541220 is about 25798.0855878881. The cubic root of 665541220 is about 873.0886037397.

Adding to 665541220 its reverse (22145566), we get a palindrome (687686786).

The spelling of 665541220 in words is "six hundred sixty-five million, five hundred forty-one thousand, two hundred twenty".