665520038400 has 360 divisors, whose sum is σ = 2557450486800. Its totient is φ = 152118435840.

The previous prime is 665520038387. The next prime is 665520038413. The reversal of 665520038400 is 4830025566.

It is an interprime number because it is at equal distance from previous prime (665520038387) and next prime (665520038413).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1704751 + ... + 2058449.

It is an arithmetic number, because the mean of its divisors is an integer number (7104029130).

Almost surely, 2^665520038400 is an apocalyptic number.

665520038400 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 665520038400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1278725243400).

665520038400 is an abundant number, since it is smaller than the sum of its proper divisors (1891930448400).

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

665520038400 is a wasteful number, since it uses less digits than its factorization.

665520038400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 353744 (or 353716 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 39.

The spelling of 665520038400 in words is "six hundred sixty-five billion, five hundred twenty million, thirty-eight thousand, four hundred".