1665244979856 has 240 divisors, whose sum is σ = 5110501032000. Its totient is φ = 504343203840.

The previous prime is 1665244979821. The next prime is 1665244979857. The reversal of 1665244979856 is 6589794425661.

1665244979856 is a `hidden beast` number, since 1 + 6 + 6 + 52 + 4 + 497 + 9 + 85 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is not an unprimeable number, because it can be changed into a prime (1665244979857) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6492580 + ... + 6744188.

It is an arithmetic number, because the mean of its divisors is an integer number (21293754300).

Almost surely, 2^{1665244979856} is an apocalyptic number.

1665244979856 is a gapful number since it is divisible by the number (16) 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 1665244979856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2555250516000).

1665244979856 is an abundant number, since it is smaller than the sum of its proper divisors (3445256052144).

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

1665244979856 is a wasteful number, since it uses less digits than its factorization.

1665244979856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251742 (or 251733 counting only the distinct ones).

The product of its digits is 783820800, while the sum is 72.

The spelling of 1665244979856 in words is "one trillion, six hundred sixty-five billion, two hundred forty-four million, nine hundred seventy-nine thousand, eight hundred fifty-six".