1781297856 has 252 divisors, whose sum is σ = 5728441680. Its totient is φ = 528353280.

The previous prime is 1781297839. The next prime is 1781297863. The reversal of 1781297856 is 6587921871.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2822661 + ... + 2823291.

Almost surely, 2^1781297856 is an apocalyptic number.

1781297856 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 1781297856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2864220840).

1781297856 is an abundant number, since it is smaller than the sum of its proper divisors (3947143824).

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

1781297856 is a wasteful number, since it uses less digits than its factorization.

1781297856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 704 (or 678 counting only the distinct ones).

The product of its digits is 1693440, while the sum is 54.

The square root of 1781297856 is about 42205.4244854853. The cubic root of 1781297856 is about 1212.2127522475.

The spelling of 1781297856 in words is "one billion, seven hundred eighty-one million, two hundred ninety-seven thousand, eight hundred fifty-six".