21240441520 has 20 divisors (see below), whose sum is σ = 49384026720. Its totient is φ = 8496176576.

The previous prime is 21240441479. The next prime is 21240441641. The reversal of 21240441520 is 2514404212.

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-3 number, since 3×21240441520³ (a number of 32 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 132752680 + ... + 132752839.

It is an arithmetic number, because the mean of its divisors is an integer number (2469201336).

Almost surely, 2^21240441520 is an apocalyptic number.

21240441520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21240441520 is an abundant number, since it is smaller than the sum of its proper divisors (28143585200).

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

21240441520 is a wasteful number, since it uses less digits than its factorization.

21240441520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265505532 (or 265505526 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 25.

Adding to 21240441520 its reverse (2514404212), we get a palindrome (23754845732).

The spelling of 21240441520 in words is "twenty-one billion, two hundred forty million, four hundred forty-one thousand, five hundred twenty".