21043551241 has 4 divisors (see below), whose sum is σ = 21044188800. Its totient is φ = 21042913684.

The previous prime is 21043551233. The next prime is 21043551301. The reversal of 21043551241 is 14215534012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21043551241 - 2³ = 21043551233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21043551041) 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, 266401 + ... + 336238.

It is an arithmetic number, because the mean of its divisors is an integer number (5261047200).

Almost surely, 2^21043551241 is an apocalyptic number.

It is an amenable number.

21043551241 is a deficient number, since it is larger than the sum of its proper divisors (637559).

21043551241 is an equidigital number, since it uses as much as digits as its factorization.

21043551241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 637558.

The product of its (nonzero) digits is 4800, while the sum is 28.

The spelling of 21043551241 in words is "twenty-one billion, forty-three million, five hundred fifty-one thousand, two hundred forty-one".