21342105520 has 20 divisors (see below), whose sum is σ = 49620395520. Its totient is φ = 8536842176.

The previous prime is 21342105503. The next prime is 21342105523. The reversal of 21342105520 is 2550124312.

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

It is not an unprimeable number, because it can be changed into a prime (21342105523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 133388080 + ... + 133388239.

It is an arithmetic number, because the mean of its divisors is an integer number (2481019776).

Almost surely, 2^21342105520 is an apocalyptic number.

21342105520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21342105520 is an abundant number, since it is smaller than the sum of its proper divisors (28278290000).

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

21342105520 is a wasteful number, since it uses less digits than its factorization.

21342105520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266776332 (or 266776326 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

Adding to 21342105520 its reverse (2550124312), we get a palindrome (23892229832).

The spelling of 21342105520 in words is "twenty-one billion, three hundred forty-two million, one hundred five thousand, five hundred twenty".