21451133244 has 12 divisors (see below), whose sum is σ = 50052644264. Its totient is φ = 7150377744.

The previous prime is 21451133243. The next prime is 21451133251. The reversal of 21451133244 is 44233115412.

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

It is a super-2 number, since 2×21451133244² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21451133243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 893797207 + ... + 893797230.

Almost surely, 2^21451133244 is an apocalyptic number.

It is an amenable number.

21451133244 is an abundant number, since it is smaller than the sum of its proper divisors (28601511020).

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

21451133244 is a wasteful number, since it uses less digits than its factorization.

21451133244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1787594444 (or 1787594442 counting only the distinct ones).

The product of its digits is 11520, while the sum is 30.

Adding to 21451133244 its reverse (44233115412), we get a palindrome (65684248656).

The spelling of 21451133244 in words is "twenty-one billion, four hundred fifty-one million, one hundred thirty-three thousand, two hundred forty-four".