21513440020 has 24 divisors (see below), whose sum is σ = 45180979200. Its totient is φ = 8604851232.

The previous prime is 21513439999. The next prime is 21513440021. The reversal of 21513440020 is 2004431512.

It is a junction number, because it is equal to n+sod(n) for n = 21513439973 and 21513440000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21513440021) 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, 633021 + ... + 666139.

It is an arithmetic number, because the mean of its divisors is an integer number (1882540800).

Almost surely, 2^21513440020 is an apocalyptic number.

21513440020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21513440020 is an abundant number, since it is smaller than the sum of its proper divisors (23667539180).

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

21513440020 is a wasteful number, since it uses less digits than its factorization.

21513440020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65607 (or 65605 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

Adding to 21513440020 its reverse (2004431512), we get a palindrome (23517871532).

The spelling of 21513440020 in words is "twenty-one billion, five hundred thirteen million, four hundred forty thousand, twenty".