21455033520 has 40 divisors (see below), whose sum is σ = 66510604656. Its totient is φ = 5721342208.

The previous prime is 21455033503. The next prime is 21455033531. The reversal of 21455033520 is 2533055412.

It is a tau number, because it is divible by the number of its divisors (40).

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

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 44697747 + ... + 44698226.

Almost surely, 2^21455033520 is an apocalyptic number.

21455033520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21455033520 is an abundant number, since it is smaller than the sum of its proper divisors (45055571136).

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

21455033520 is a wasteful number, since it uses less digits than its factorization.

21455033520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89395989 (or 89395983 counting only the distinct ones).

The product of its (nonzero) digits is 18000, while the sum is 30.

Adding to 21455033520 its reverse (2533055412), we get a palindrome (23988088932).

The spelling of 21455033520 in words is "twenty-one billion, four hundred fifty-five million, thirty-three thousand, five hundred twenty".