21221042243 has 8 divisors (see below), whose sum is σ = 21286084608. Its totient is φ = 21156050824.

The previous prime is 21221042177. The next prime is 21221042261. The reversal of 21221042243 is 34224012212.

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 21221042243 - 2¹² = 21221038147 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221042443) 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, 925880 + ... + 948522.

It is an arithmetic number, because the mean of its divisors is an integer number (2660760576).

Almost surely, 2^21221042243 is an apocalyptic number.

21221042243 is a deficient number, since it is larger than the sum of its proper divisors (65042365).

21221042243 is a wasteful number, since it uses less digits than its factorization.

21221042243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25473.

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 21221042243 its reverse (34224012212), we get a palindrome (55445054455).

The spelling of 21221042243 in words is "twenty-one billion, two hundred twenty-one million, forty-two thousand, two hundred forty-three".