1285181465820 has 384 divisors, whose sum is σ = 4489879296000. Its totient is φ = 273727641600.

The previous prime is 1285181465779. The next prime is 1285181465857. The reversal of 1285181465820 is 285641815821.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 23825280 + ... + 23879160.

It is an arithmetic number, because the mean of its divisors is an integer number (11692394000).

Almost surely, 2^{1285181465820} is an apocalyptic number.

1285181465820 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 1285181465820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2244939648000).

1285181465820 is an abundant number, since it is smaller than the sum of its proper divisors (3204697830180).

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

1285181465820 is a wasteful number, since it uses less digits than its factorization.

1285181465820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53994 (or 53978 counting only the distinct ones).

The product of its (nonzero) digits is 1228800, while the sum is 51.

The spelling of 1285181465820 in words is "one trillion, two hundred eighty-five billion, one hundred eighty-one million, four hundred sixty-five thousand, eight hundred twenty".