21020531040 has 144 divisors (see below), whose sum is σ = 72715563648. Its totient is φ = 5528659968.

The previous prime is 21020531017. The next prime is 21020531053. The reversal of 21020531040 is 4013502012.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5137 + ... + 205103.

It is an arithmetic number, because the mean of its divisors is an integer number (504969192).

Almost surely, 2^21020531040 is an apocalyptic number.

21020531040 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 21020531040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36357781824).

21020531040 is an abundant number, since it is smaller than the sum of its proper divisors (51695032608).

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

21020531040 is a wasteful number, since it uses less digits than its factorization.

21020531040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 200061 (or 200050 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The spelling of 21020531040 in words is "twenty-one billion, twenty million, five hundred thirty-one thousand, forty".