1665223124400 has 360 divisors, whose sum is σ = 6365351805696. Its totient is φ = 399770150400.

The previous prime is 1665223124399. The next prime is 1665223124413. The reversal of 1665223124400 is 44213225661.

1665223124400 is a `hidden beast` number, since 1 + 6 + 6 + 5 + 223 + 1 + 24 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (360).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 3874669 + ... + 4282931.

Almost surely, 2^{1665223124400} is an apocalyptic number.

1665223124400 is a gapful number since it is divisible by the number (10) 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 1665223124400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3182675902848).

1665223124400 is an abundant number, since it is smaller than the sum of its proper divisors (4700128681296).

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

1665223124400 is a wasteful number, since it uses less digits than its factorization.

1665223124400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 408401 (or 408387 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The spelling of 1665223124400 in words is "one trillion, six hundred sixty-five billion, two hundred twenty-three million, one hundred twenty-four thousand, four hundred".