21451002444 has 24 divisors (see below), whose sum is σ = 55613710320. Its totient is φ = 7150334112.

The previous prime is 21451002427. The next prime is 21451002449. The reversal of 21451002444 is 44420015412.

21451002444 is a `hidden beast` number, since 214 + 5 + 1 + 0 + 0 + 2 + 444 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21451002449) 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 7 ways as a sum of consecutive naturals, for example, 99310089 + ... + 99310304.

It is an arithmetic number, because the mean of its divisors is an integer number (2317237930).

Almost surely, 2^21451002444 is an apocalyptic number.

It is an amenable number.

21451002444 is an abundant number, since it is smaller than the sum of its proper divisors (34162707876).

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

21451002444 is a wasteful number, since it uses less digits than its factorization.

21451002444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198620406 (or 198620398 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 27.

Adding to 21451002444 its reverse (44420015412), we get a palindrome (65871017856).

The spelling of 21451002444 in words is "twenty-one billion, four hundred fifty-one million, two thousand, four hundred forty-four".