21544451331 has 32 divisors (see below), whose sum is σ = 31950643200. Its totient is φ = 12823574400.

The previous prime is 21544451297. The next prime is 21544451351. The reversal of 21544451331 is 13315444512.

It is not a de Polignac number, because 21544451331 - 2¹⁸ = 21544189187 is a prime.

It is a super-2 number, since 2×21544451331² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21544451292 and 21544451301.

It is not an unprimeable number, because it can be changed into a prime (21544451351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3078246 + ... + 3085236.

It is an arithmetic number, because the mean of its divisors is an integer number (998457600).

Almost surely, 2^21544451331 is an apocalyptic number.

21544451331 is a deficient number, since it is larger than the sum of its proper divisors (10406191869).

21544451331 is a wasteful number, since it uses less digits than its factorization.

21544451331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9587.

The product of its digits is 28800, while the sum is 33.

Adding to 21544451331 its reverse (13315444512), we get a palindrome (34859895843).

The spelling of 21544451331 in words is "twenty-one billion, five hundred forty-four million, four hundred fifty-one thousand, three hundred thirty-one".