21455333444 has 24 divisors (see below), whose sum is σ = 39914313600. Its totient is φ = 10062424800.

The previous prime is 21455333423. The next prime is 21455333447. The reversal of 21455333444 is 44433355412.

It is a super-2 number, since 2×21455333444² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a junction number, because it is equal to n+sod(n) for n = 21455333398 and 21455333407.

It is not an unprimeable number, because it can be changed into a prime (21455333447) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1389884 + ... + 1405235.

It is an arithmetic number, because the mean of its divisors is an integer number (1663096400).

Almost surely, 2^21455333444 is an apocalyptic number.

It is an amenable number.

21455333444 is a deficient number, since it is larger than the sum of its proper divisors (18458980156).

21455333444 is a wasteful number, since it uses less digits than its factorization.

21455333444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2795243 (or 2795241 counting only the distinct ones).

The product of its digits is 345600, while the sum is 38.

Adding to 21455333444 its reverse (44433355412), we get a palindrome (65888688856).

The spelling of 21455333444 in words is "twenty-one billion, four hundred fifty-five million, three hundred thirty-three thousand, four hundred forty-four".