665306556420 has 192 divisors, whose sum is σ = 2124323389440. Its totient is φ = 154107532800.

The previous prime is 665306556403. The next prime is 665306556487. The reversal of 665306556420 is 24655603566.

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 665306556420.

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, 1410534 + ... + 1822146.

It is an arithmetic number, because the mean of its divisors is an integer number (11064184320).

Almost surely, 2^665306556420 is an apocalyptic number.

665306556420 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 665306556420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1062161694720).

665306556420 is an abundant number, since it is smaller than the sum of its proper divisors (1459016833020).

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

665306556420 is a wasteful number, since it uses less digits than its factorization.

665306556420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411746 (or 411744 counting only the distinct ones).

The product of its (nonzero) digits is 3888000, while the sum is 48.

The spelling of 665306556420 in words is "six hundred sixty-five billion, three hundred six million, five hundred fifty-six thousand, four hundred twenty".