11051981 has 4 divisors (see below), whose sum is σ = 11203452. Its totient is φ = 10900512.

The previous prime is 11051959. The next prime is 11051993. The reversal of 11051981 is 18915011.

11051981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18915011 = 53 ⋅356887.

It can be written as a sum of positive squares in 2 ways, for example, as 8649481 + 2402500 = 2941^2 + 1550^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11051981 is a prime.

It is a super-2 number, since 2×11051981² = 244292568048722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11051981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11051951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75626 + ... + 75771.

It is an arithmetic number, because the mean of its divisors is an integer number (2800863).

Almost surely, 2^11051981 is an apocalyptic number.

It is an amenable number.

11051981 is a deficient number, since it is larger than the sum of its proper divisors (151471).

11051981 is an equidigital number, since it uses as much as digits as its factorization.

11051981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151470.

The product of its (nonzero) digits is 360, while the sum is 26.

The square root of 11051981 is about 3324.4519849142. The cubic root of 11051981 is about 222.7477759879.

Adding to 11051981 its reverse (18915011), we get a palindrome (29966992).

The spelling of 11051981 in words is "eleven million, fifty-one thousand, nine hundred eighty-one".