21071841 has 16 divisors (see below), whose sum is σ = 33506304. Its totient is φ = 11517264.

The previous prime is 21071837. The next prime is 21071851. The reversal of 21071841 is 14817012.

It is not a de Polignac number, because 21071841 - 2² = 21071837 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21071801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21331 + ... + 22296.

It is an arithmetic number, because the mean of its divisors is an integer number (2094144).

Almost surely, 2^21071841 is an apocalyptic number.

21071841 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21071841 is a deficient number, since it is larger than the sum of its proper divisors (12434463).

21071841 is a wasteful number, since it uses less digits than its factorization.

21071841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43660.

The product of its (nonzero) digits is 448, while the sum is 24.

The square root of 21071841 is about 4590.4074982511. The cubic root of 21071841 is about 276.2066688792.

Adding to 21071841 its reverse (14817012), we get a palindrome (35888853).

It can be divided in two parts, 21071 and 841, that added together give a palindrome (21912).

The spelling of 21071841 in words is "twenty-one million, seventy-one thousand, eight hundred forty-one".