666435420 has 144 divisors (see below), whose sum is σ = 2316787200. Its totient is φ = 151901568.

The previous prime is 666435401. The next prime is 666435439. The reversal of 666435420 is 24534666.

It is an interprime number because it is at equal distance from previous prime (666435401) and next prime (666435439).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 754299 + ... + 755181.

It is an arithmetic number, because the mean of its divisors is an integer number (16088800).

Almost surely, 2^666435420 is an apocalyptic number.

666435420 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 666435420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1158393600).

666435420 is an abundant number, since it is smaller than the sum of its proper divisors (1650351780).

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

666435420 is a wasteful number, since it uses less digits than its factorization.

666435420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1504 (or 1499 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 36.

The square root of 666435420 is about 25815.4105138772. The cubic root of 666435420 is about 873.4794467701.

The spelling of 666435420 in words is "six hundred sixty-six million, four hundred thirty-five thousand, four hundred twenty".