21020134536 has 96 divisors (see below), whose sum is σ = 59875096320. Its totient is φ = 6652713600.

The previous prime is 21020134529. The next prime is 21020134537. The reversal of 21020134536 is 63543102012.

21020134536 is a `hidden beast` number, since 2 + 1 + 0 + 201 + 3 + 453 + 6 = 666.

It is not an unprimeable number, because it can be changed into a prime (21020134537) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 29451 + ... + 207141.

It is an arithmetic number, because the mean of its divisors is an integer number (623698920).

Almost surely, 2^21020134536 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21020134536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29937548160).

21020134536 is an abundant number, since it is smaller than the sum of its proper divisors (38854961784).

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

21020134536 is a wasteful number, since it uses less digits than its factorization.

21020134536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177787 (or 177780 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

Adding to 21020134536 its reverse (63543102012), we get a palindrome (84563236548).

The spelling of 21020134536 in words is "twenty-one billion, twenty million, one hundred thirty-four thousand, five hundred thirty-six".