1081686321 has 27 divisors (see below), whose sum is σ = 1651860171. Its totient is φ = 681986304.

The previous prime is 1081686311. The next prime is 1081686337. The reversal of 1081686321 is 1236861801.

The square root of 1081686321 is 32889.

It is a perfect power (a square), and thus also a powerful number.

1081686321 is a `hidden beast` number, since 1 + 0 + 8 + 16 + 8 + 632 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1074200625 + 7485696 = 32775^2 + 2736^2 .

It is not a de Polignac number, because 1081686321 - 2²¹ = 1079589169 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1081686311) by changing a digit.

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 26 ways as a sum of consecutive naturals, for example, 1874385 + ... + 1874961.

Almost surely, 2^1081686321 is an apocalyptic number.

1081686321 is the 32889-th square number.

1081686321 is the 16445-th centered octagonal number.

It is an amenable number.

1081686321 is a deficient number, since it is larger than the sum of its proper divisors (570173850).

1081686321 is an frugal number, since it uses more digits than its factorization.

1081686321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1198 (or 599 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The cubic root of 1081686321 is about 1026.5192844578.

Multiplying 1081686321 by its sum of digits (36), we get a square (38940707556 = 197334²).

The spelling of 1081686321 in words is "one billion, eighty-one million, six hundred eighty-six thousand, three hundred twenty-one".