666464 has 24 divisors (see below), whose sum is σ = 1338120. Its totient is φ = 326656.

The previous prime is 666461. The next prime is 666467. The reversal of 666464 is 464666.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (666461) and next prime (666467).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a self number, because there is not a number n which added to its sum of digits gives 666464.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666461) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1712 + ... + 2064.

It is an arithmetic number, because the mean of its divisors is an integer number (55755).

2⁶⁶⁶⁴⁶⁴ 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 666464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (669060).

666464 is an abundant number, since it is smaller than the sum of its proper divisors (671656).

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

666464 is a wasteful number, since it uses less digits than its factorization.

666464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422 (or 414 counting only the distinct ones).

The product of its digits is 20736, while the sum is 32.

The square root of 666464 is about 816.3724640138. The cubic root of 666464 is about 87.3491932944.

It can be divided in two parts, 66 and 6464, that multiplied together give a palindrome (426624).

The spelling of 666464 in words is "six hundred sixty-six thousand, four hundred sixty-four".