665536998720 has 448 divisors, whose sum is σ = 2392772659200. Its totient is φ = 155249418240.

The previous prime is 665536998701. The next prime is 665536998769. The reversal of 665536998720 is 27899635566.

It is a happy number.

It is a Smith number, since the sum of its digits (66) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (66).

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, 94012141 + ... + 94019219.

It is an arithmetic number, because the mean of its divisors is an integer number (5341010400).

Almost surely, 2^665536998720 is an apocalyptic number.

665536998720 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 665536998720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1196386329600).

665536998720 is an abundant number, since it is smaller than the sum of its proper divisors (1727235660480).

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

665536998720 is a wasteful number, since it uses less digits than its factorization.

665536998720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7446 (or 7436 counting only the distinct ones).

The product of its (nonzero) digits is 146966400, while the sum is 66.

The spelling of 665536998720 in words is "six hundred sixty-five billion, five hundred thirty-six million, nine hundred ninety-eight thousand, seven hundred twenty".