21154260243 has 4 divisors (see below), whose sum is σ = 28205680328. Its totient is φ = 14102840160.

The previous prime is 21154260187. The next prime is 21154260287. The reversal of 21154260243 is 34206245112.

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

It is not a de Polignac number, because 21154260243 - 2¹³ = 21154252051 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21154260243.

It is not an unprimeable number, because it can be changed into a prime (21154260443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3525710038 + ... + 3525710043.

It is an arithmetic number, because the mean of its divisors is an integer number (7051420082).

Almost surely, 2^21154260243 is an apocalyptic number.

21154260243 is a deficient number, since it is larger than the sum of its proper divisors (7051420085).

21154260243 is an equidigital number, since it uses as much as digits as its factorization.

21154260243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7051420084.

The product of its (nonzero) digits is 11520, while the sum is 30.

The spelling of 21154260243 in words is "twenty-one billion, one hundred fifty-four million, two hundred sixty thousand, two hundred forty-three".