21455104440 has 128 divisors (see below), whose sum is σ = 80247697920. Its totient is φ = 4458201600.

The previous prime is 21455104381. The next prime is 21455104459. The reversal of 21455104440 is 4440155412.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 21455104398 and 21455104407.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1151751 + ... + 1170230.

It is an arithmetic number, because the mean of its divisors is an integer number (626935140).

Almost surely, 2^21455104440 is an apocalyptic number.

21455104440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21455104440 is an abundant number, since it is smaller than the sum of its proper divisors (58792593480).

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

21455104440 is a wasteful number, since it uses less digits than its factorization.

21455104440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2322013 (or 2322009 counting only the distinct ones).

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

Adding to 21455104440 its reverse (4440155412), we get a palindrome (25895259852).

The spelling of 21455104440 in words is "twenty-one billion, four hundred fifty-five million, one hundred four thousand, four hundred forty".