665642580 has 192 divisors, whose sum is σ = 2067394560. Its totient is φ = 159376896.

The previous prime is 665642573. The next prime is 665642647. The reversal of 665642580 is 85246566.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1813557 + ... + 1813923.

It is an arithmetic number, because the mean of its divisors is an integer number (10767680).

Almost surely, 2^665642580 is an apocalyptic number.

665642580 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 665642580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1033697280).

665642580 is an abundant number, since it is smaller than the sum of its proper divisors (1401751980).

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

665642580 is a wasteful number, since it uses less digits than its factorization.

665642580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 478 (or 476 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 42.

The square root of 665642580 is about 25800.0499999516. The cubic root of 665642580 is about 873.1329244449.

The spelling of 665642580 in words is "six hundred sixty-five million, six hundred forty-two thousand, five hundred eighty".