1665213551456 has 288 divisors, whose sum is σ = 4221339107328. Its totient is φ = 632438876160.

The previous prime is 1665213551437. The next prime is 1665213551479. The reversal of 1665213551456 is 6541553125661.

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, 149033486 + ... + 149044658.

It is an arithmetic number, because the mean of its divisors is an integer number (14657427456).

Almost surely, 2^{1665213551456} is an apocalyptic number.

1665213551456 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 1665213551456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2110669553664).

1665213551456 is an abundant number, since it is smaller than the sum of its proper divisors (2556125555872).

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

1665213551456 is a wasteful number, since it uses less digits than its factorization.

1665213551456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11374 (or 11353 counting only the distinct ones).

The product of its digits is 3240000, while the sum is 50.

The spelling of 1665213551456 in words is "one trillion, six hundred sixty-five billion, two hundred thirteen million, five hundred fifty-one thousand, four hundred fifty-six".