21203240243 has 8 divisors (see below), whose sum is σ = 21261229056. Its totient is φ = 21145293000.

The previous prime is 21203240231. The next prime is 21203240281. The reversal of 21203240243 is 34204230212.

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

It is a cyclic number.

It is not a de Polignac number, because 21203240243 - 2¹⁴ = 21203223859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21203240543) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1199318 + ... + 1216868.

It is an arithmetic number, because the mean of its divisors is an integer number (2657653632).

Almost surely, 2^21203240243 is an apocalyptic number.

21203240243 is a deficient number, since it is larger than the sum of its proper divisors (57988813).

21203240243 is a wasteful number, since it uses less digits than its factorization.

21203240243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20785.

The product of its (nonzero) digits is 2304, while the sum is 23.

Adding to 21203240243 its reverse (34204230212), we get a palindrome (55407470455).

The spelling of 21203240243 in words is "twenty-one billion, two hundred three million, two hundred forty thousand, two hundred forty-three".