21200535520 has 24 divisors (see below), whose sum is σ = 50086265544. Its totient is φ = 8480214144.

The previous prime is 21200535509. The next prime is 21200535523. The reversal of 21200535520 is 2553500212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200535523) 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, 66251514 + ... + 66251833.

It is an arithmetic number, because the mean of its divisors is an integer number (2086927731).

Almost surely, 2^21200535520 is an apocalyptic number.

21200535520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21200535520 is an abundant number, since it is smaller than the sum of its proper divisors (28885730024).

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

21200535520 is a wasteful number, since it uses less digits than its factorization.

21200535520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132503362 (or 132503354 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 25.

The spelling of 21200535520 in words is "twenty-one billion, two hundred million, five hundred thirty-five thousand, five hundred twenty".