665585078400 has 3072 divisors, whose sum is σ = 3059804160000. Its totient is φ = 139345920000.

The previous prime is 665585078339. The next prime is 665585078471. The reversal of 665585078400 is 4870585566.

665585078400 is a `hidden beast` number, since 6 + 6 + 5 + 58 + 507 + 84 + 0 + 0 = 666.

665585078400 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 16233782380 + ... + 16233782420.

It is an arithmetic number, because the mean of its divisors is an integer number (996030000).

Almost surely, 2^665585078400 is an apocalyptic number.

665585078400 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 665585078400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1529902080000).

665585078400 is an abundant number, since it is smaller than the sum of its proper divisors (2394219081600).

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

665585078400 is a wasteful number, since it uses less digits than its factorization.

665585078400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164 (or 141 counting only the distinct ones).

The product of its (nonzero) digits is 8064000, while the sum is 54.

The spelling of 665585078400 in words is "six hundred sixty-five billion, five hundred eighty-five million, seventy-eight thousand, four hundred".