21181141 has 4 divisors (see below), whose sum is σ = 21234892. Its totient is φ = 21127392.

The previous prime is 21181117. The next prime is 21181157. The reversal of 21181141 is 14118112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16892100 + 4289041 = 4110^2 + 2071^2 .

It is a cyclic number.

It is not a de Polignac number, because 21181141 - 2⁵ = 21181109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131141) 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, 26280 + ... + 27073.

It is an arithmetic number, because the mean of its divisors is an integer number (5308723).

Almost surely, 2^21181141 is an apocalyptic number.

It is an amenable number.

21181141 is a deficient number, since it is larger than the sum of its proper divisors (53751).

21181141 is an equidigital number, since it uses as much as digits as its factorization.

21181141 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53750.

The product of its digits is 64, while the sum is 19.

The square root of 21181141 is about 4602.2973611013. The cubic root of 21181141 is about 276.6834084480.

Adding to 21181141 its reverse (14118112), we get a palindrome (35299253).

The spelling of 21181141 in words is "twenty-one million, one hundred eighty-one thousand, one hundred forty-one".