1781000000 has 196 divisors, whose sum is σ = 4792204284. Its totient is φ = 652800000.

The previous prime is 1780999991. The next prime is 1781000029. The reversal of 1781000000 is 1871.

It can be written as a sum of positive squares in 14 ways, for example, as 1250895424 + 530104576 = 35368^2 + 23024^2 .

It is a super-2 number, since 2×1781000000² = 6343922000000000000, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 12999932 + ... + 13000068.

Almost surely, 2^1781000000 is an apocalyptic number.

1781000000 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 1781000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2396102142).

1781000000 is an abundant number, since it is smaller than the sum of its proper divisors (3011204284).

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

1781000000 is an frugal number, since it uses more digits than its factorization.

1781000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192 (or 157 counting only the distinct ones).

The product of its (nonzero) digits is 56, while the sum is 17.

The square root of 1781000000 is about 42201.8956920184. The cubic root of 1781000000 is about 1212.1451826068.

Adding to 1781000000 its reverse (1871), we get a palindrome (1781001871).

The spelling of 1781000000 in words is "one billion, seven hundred eighty-one million", and thus it is an aban number.