21161841 has 8 divisors (see below), whose sum is σ = 28264704. Its totient is φ = 14083440.

The previous prime is 21161783. The next prime is 21161857. The reversal of 21161841 is 14816112.

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

It is a de Polignac number, because none of the positive numbers 2^k-21161841 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21161641) 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 7 ways as a sum of consecutive naturals, for example, 3990 + ... + 7631.

It is an arithmetic number, because the mean of its divisors is an integer number (3533088).

Almost surely, 2^21161841 is an apocalyptic number.

It is an amenable number.

21161841 is a deficient number, since it is larger than the sum of its proper divisors (7102863).

21161841 is a wasteful number, since it uses less digits than its factorization.

21161841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12231.

The product of its digits is 384, while the sum is 24.

The square root of 21161841 is about 4600.2001043433. The cubic root of 21161841 is about 276.5993460500.

Adding to 21161841 its reverse (14816112), we get a palindrome (35977953).

The spelling of 21161841 in words is "twenty-one million, one hundred sixty-one thousand, eight hundred forty-one".