21420234233 has 4 divisors (see below), whose sum is σ = 21420567168. Its totient is φ = 21419901300.

The previous prime is 21420234211. The next prime is 21420234257. The reversal of 21420234233 is 33243202412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21420234233 - 2¹⁴ = 21420217849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21420234293) 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, 35741 + ... + 210042.

It is an arithmetic number, because the mean of its divisors is an integer number (5355141792).

Almost surely, 2^21420234233 is an apocalyptic number.

It is an amenable number.

21420234233 is a deficient number, since it is larger than the sum of its proper divisors (332935).

21420234233 is an equidigital number, since it uses as much as digits as its factorization.

21420234233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332934.

The product of its (nonzero) digits is 6912, while the sum is 26.

Adding to 21420234233 its reverse (33243202412), we get a palindrome (54663436645).

The spelling of 21420234233 in words is "twenty-one billion, four hundred twenty million, two hundred thirty-four thousand, two hundred thirty-three".