1665739837440 has 1872 divisors, whose sum is σ = 7499026941120. Its totient is φ = 338889277440.

The previous prime is 1665739837429. The next prime is 1665739837469. The reversal of 1665739837440 is 447389375661.

It is a happy number.

1665739837440 is a `hidden beast` number, since 1 + 6 + 6 + 5 + 73 + 98 + 37 + 440 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 2917232355 + ... + 2917232925.

It is an arithmetic number, because the mean of its divisors is an integer number (4005890460).

Almost surely, 2^{1665739837440} is an apocalyptic number.

1665739837440 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 1665739837440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3749513470560).

1665739837440 is an abundant number, since it is smaller than the sum of its proper divisors (5833287103680).

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

1665739837440 is a wasteful number, since it uses less digits than its factorization.

1665739837440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 656 (or 624 counting only the distinct ones).

The product of its (nonzero) digits is 91445760, while the sum is 63.

The spelling of 1665739837440 in words is "one trillion, six hundred sixty-five billion, seven hundred thirty-nine million, eight hundred thirty-seven thousand, four hundred forty".