658666640 has 80 divisors (see below), whose sum is σ = 1637145216. Its totient is φ = 245836800.

The previous prime is 658666633. The next prime is 658666643. The reversal of 658666640 is 46666856.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (658666643) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 71075 + ... + 79805.

Almost surely, 2^658666640 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 658666640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (818572608).

658666640 is an abundant number, since it is smaller than the sum of its proper divisors (978478576).

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

658666640 is a wasteful number, since it uses less digits than its factorization.

658666640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8808 (or 8802 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 47.

The square root of 658666640 is about 25664.5015537025. The cubic root of 658666640 is about 870.0720599141.

The spelling of 658666640 in words is "six hundred fifty-eight million, six hundred sixty-six thousand, six hundred forty".