21240225223 has 4 divisors (see below), whose sum is σ = 24274543120. Its totient is φ = 18205907328.

The previous prime is 21240225199. The next prime is 21240225233. The reversal of 21240225223 is 32252204212.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-21240225223 is a prime.

It is a super-2 number, since 2×21240225223² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21240225233) 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, 1517158938 + ... + 1517158951.

It is an arithmetic number, because the mean of its divisors is an integer number (6068635780).

Almost surely, 2^21240225223 is an apocalyptic number.

21240225223 is a deficient number, since it is larger than the sum of its proper divisors (3034317897).

21240225223 is an equidigital number, since it uses as much as digits as its factorization.

21240225223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3034317896.

The product of its (nonzero) digits is 3840, while the sum is 25.

Adding to 21240225223 its reverse (32252204212), we get a palindrome (53492429435).

The spelling of 21240225223 in words is "twenty-one billion, two hundred forty million, two hundred twenty-five thousand, two hundred twenty-three".