21154443243 has 8 divisors (see below), whose sum is σ = 28209920400. Its totient is φ = 14100964128.

The previous prime is 21154443227. The next prime is 21154443259. The reversal of 21154443243 is 34234445112.

It is an interprime number because it is at equal distance from previous prime (21154443227) and next prime (21154443259).

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

It is not a de Polignac number, because 21154443243 - 2⁴ = 21154443227 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21154443643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 474628 + ... + 517281.

It is an arithmetic number, because the mean of its divisors is an integer number (3526240050).

Almost surely, 2^21154443243 is an apocalyptic number.

21154443243 is a deficient number, since it is larger than the sum of its proper divisors (7055477157).

21154443243 is an equidigital number, since it uses as much as digits as its factorization.

21154443243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 999021.

The product of its digits is 46080, while the sum is 33.

Adding to 21154443243 its reverse (34234445112), we get a palindrome (55388888355).

The spelling of 21154443243 in words is "twenty-one billion, one hundred fifty-four million, four hundred forty-three thousand, two hundred forty-three".