1665213987200 has 384 divisors, whose sum is σ = 4228289640000. Its totient is φ = 647884800000.

The previous prime is 1665213987131. The next prime is 1665213987257. The reversal of 1665213987200 is 27893125661.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (50).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7271676686 + ... + 7271676914.

Almost surely, 2^{1665213987200} is an apocalyptic number.

1665213987200 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 1665213987200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2114144820000).

1665213987200 is an abundant number, since it is smaller than the sum of its proper divisors (2563075652800).

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

1665213987200 is a wasteful number, since it uses less digits than its factorization.

1665213987200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 654 (or 637 counting only the distinct ones).

The product of its (nonzero) digits is 1088640, while the sum is 50.

The spelling of 1665213987200 in words is "one trillion, six hundred sixty-five billion, two hundred thirteen million, nine hundred eighty-seven thousand, two hundred".