1161781321 has 8 divisors (see below), whose sum is σ = 1171719360. Its totient is φ = 1151866128.

The previous prime is 1161781301. The next prime is 1161781333. The reversal of 1161781321 is 1231871611.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1161781321 - 2¹⁷ = 1161650249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1161781301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 105540 + ... + 116026.

It is an arithmetic number, because the mean of its divisors is an integer number (146464920).

Almost surely, 2^1161781321 is an apocalyptic number.

It is an amenable number.

1161781321 is a deficient number, since it is larger than the sum of its proper divisors (9938039).

1161781321 is a wasteful number, since it uses less digits than its factorization.

1161781321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11423.

The product of its digits is 2016, while the sum is 31.

The square root of 1161781321 is about 34084.9133928781. The cubic root of 1161781321 is about 1051.2551342803.

The spelling of 1161781321 in words is "one billion, one hundred sixty-one million, seven hundred eighty-one thousand, three hundred twenty-one".