1161981 has 24 divisors (see below), whose sum is σ = 1782144. Its totient is φ = 728640.

The previous prime is 1161949. The next prime is 1161991. The reversal of 1161981 is 1891611.

It is not a de Polignac number, because 1161981 - 2⁵ = 1161949 is a prime.

It is a super-2 number, since 2×1161981² = 2700399688722, which contains 22 as substring.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1161931) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17310 + ... + 17376.

It is an arithmetic number, because the mean of its divisors is an integer number (74256).

2^1161981 is an apocalyptic number.

It is an amenable number.

1161981 is a deficient number, since it is larger than the sum of its proper divisors (620163).

1161981 is a wasteful number, since it uses less digits than its factorization.

1161981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161 (or 158 counting only the distinct ones).

The product of its digits is 432, while the sum is 27.

The square root of 1161981 is about 1077.9522252864. The cubic root of 1161981 is about 105.1315358336.

The spelling of 1161981 in words is "one million, one hundred sixty-one thousand, nine hundred eighty-one".