664419840 has 320 divisors, whose sum is σ = 2573835264. Its totient is φ = 142737408.

The previous prime is 664419829. The next prime is 664419851. The reversal of 664419840 is 48914466.

It is an interprime number because it is at equal distance from previous prime (664419829) and next prime (664419851).

It is a tau number, because it is divible by the number of its divisors (320).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 664419792 and 664419801.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 913557 + ... + 914283.

Almost surely, 2^664419840 is an apocalyptic number.

664419840 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 664419840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1286917632).

664419840 is an abundant number, since it is smaller than the sum of its proper divisors (1909415424).

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

664419840 is a wasteful number, since it uses less digits than its factorization.

664419840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 777 (or 761 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 42.

The square root of 664419840 is about 25776.3426420429. The cubic root of 664419840 is about 872.5979682167.

The spelling of 664419840 in words is "six hundred sixty-four million, four hundred nineteen thousand, eight hundred forty".