21220432243 has 4 divisors (see below), whose sum is σ = 21238555048. Its totient is φ = 21202309440.

The previous prime is 21220432241. The next prime is 21220432307. The reversal of 21220432243 is 34223402212.

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 21220432243 - 2¹ = 21220432241 is a prime.

It is a super-3 number, since 3×21220432243³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21220432241) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9059646 + ... + 9061987.

It is an arithmetic number, because the mean of its divisors is an integer number (5309638762).

Almost surely, 2^21220432243 is an apocalyptic number.

21220432243 is a deficient number, since it is larger than the sum of its proper divisors (18122805).

21220432243 is a wasteful number, since it uses less digits than its factorization.

21220432243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18122804.

The product of its (nonzero) digits is 4608, while the sum is 25.

Adding to 21220432243 its reverse (34223402212), we get a palindrome (55443834455).

The spelling of 21220432243 in words is "twenty-one billion, two hundred twenty million, four hundred thirty-two thousand, two hundred forty-three".