21013142243 has 4 divisors (see below), whose sum is σ = 21199099368. Its totient is φ = 20827185120.

The previous prime is 21013142239. The next prime is 21013142257. The reversal of 21013142243 is 34224131012.

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

It is a cyclic number.

It is not a de Polignac number, because 21013142243 - 2² = 21013142239 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21013142203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92978393 + ... + 92978618.

It is an arithmetic number, because the mean of its divisors is an integer number (5299774842).

Almost surely, 2^21013142243 is an apocalyptic number.

21013142243 is a deficient number, since it is larger than the sum of its proper divisors (185957125).

21013142243 is a wasteful number, since it uses less digits than its factorization.

21013142243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185957124.

The product of its (nonzero) digits is 1152, while the sum is 23.

Adding to 21013142243 its reverse (34224131012), we get a palindrome (55237273255).

The spelling of 21013142243 in words is "twenty-one billion, thirteen million, one hundred forty-two thousand, two hundred forty-three".