665601420 has 96 divisors (see below), whose sum is σ = 2067690240. Its totient is φ = 158613760.

The previous prime is 665601367. The next prime is 665601449. The reversal of 665601420 is 24106566.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30394 + ... + 47486.

It is an arithmetic number, because the mean of its divisors is an integer number (21538440).

Almost surely, 2^665601420 is an apocalyptic number.

665601420 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665601420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1033845120).

665601420 is an abundant number, since it is smaller than the sum of its proper divisors (1402088820).

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

665601420 is a wasteful number, since it uses less digits than its factorization.

665601420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17175 (or 17173 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 665601420 is about 25799.2523147474. The cubic root of 665601420 is about 873.1149273530.

Adding to 665601420 its reverse (24106566), we get a palindrome (689707986).

The spelling of 665601420 in words is "six hundred sixty-five million, six hundred one thousand, four hundred twenty".