664017640 has 128 divisors (see below), whose sum is σ = 1816214400. Its totient is φ = 215147520.

The previous prime is 664017617. The next prime is 664017661. The reversal of 664017640 is 46710466.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 664017596 and 664017605.

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, 163879 + ... + 167881.

It is an arithmetic number, because the mean of its divisors is an integer number (14189175).

Almost surely, 2^664017640 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 664017640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (908107200).

664017640 is an abundant number, since it is smaller than the sum of its proper divisors (1152196760).

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

664017640 is a wasteful number, since it uses less digits than its factorization.

664017640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4067 (or 4063 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 34.

The square root of 664017640 is about 25768.5397335588. The cubic root of 664017640 is about 872.4218598176.

The spelling of 664017640 in words is "six hundred sixty-four million, seventeen thousand, six hundred forty".