21035534520 has 512 divisors, whose sum is σ = 87038945280. Its totient is φ = 3924910080.

The previous prime is 21035534479. The next prime is 21035534537. The reversal of 21035534520 is 2543553012.

It is a super-2 number, since 2×21035534520² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 4442074 + ... + 4446806.

It is an arithmetic number, because the mean of its divisors is an integer number (169997940).

Almost surely, 2^21035534520 is an apocalyptic number.

21035534520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21035534520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43519472640).

21035534520 is an abundant number, since it is smaller than the sum of its proper divisors (66003410760).

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

21035534520 is a wasteful number, since it uses less digits than its factorization.

21035534520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4815 (or 4811 counting only the distinct ones).

The product of its (nonzero) digits is 18000, while the sum is 30.

It can be divided in two parts, 21035 and 534520, that added together give a palindrome (555555).

The spelling of 21035534520 in words is "twenty-one billion, thirty-five million, five hundred thirty-four thousand, five hundred twenty".