21210320243 has 8 divisors (see below), whose sum is σ = 24242279520. Its totient is φ = 18178839360.

The previous prime is 21210320239. The next prime is 21210320273. The reversal of 21210320243 is 34202301212.

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 21210320243 - 2² = 21210320239 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21210320273) 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, 18938 + ... + 206831.

It is an arithmetic number, because the mean of its divisors is an integer number (3030284940).

Almost surely, 2^21210320243 is an apocalyptic number.

21210320243 is a deficient number, since it is larger than the sum of its proper divisors (3031959277).

21210320243 is a wasteful number, since it uses less digits than its factorization.

21210320243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239197.

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 21210320243 its reverse (34202301212), we get a palindrome (55412621455).

The spelling of 21210320243 in words is "twenty-one billion, two hundred ten million, three hundred twenty thousand, two hundred forty-three".