21221452452 has 12 divisors (see below), whose sum is σ = 49516722416. Its totient is φ = 7073817480.

The previous prime is 21221452451. The next prime is 21221452541. The reversal of 21221452452 is 25425412212.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (21221452451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 884227174 + ... + 884227197.

Almost surely, 2^21221452452 is an apocalyptic number.

It is an amenable number.

21221452452 is an abundant number, since it is smaller than the sum of its proper divisors (28295269964).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21221452452 is a wasteful number, since it uses less digits than its factorization.

21221452452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1768454378 (or 1768454376 counting only the distinct ones).

The product of its digits is 12800, while the sum is 30.

Adding to 21221452452 its reverse (25425412212), we get a palindrome (46646864664).

The spelling of 21221452452 in words is "twenty-one billion, two hundred twenty-one million, four hundred fifty-two thousand, four hundred fifty-two".