21011010020 has 192 divisors, whose sum is σ = 60622442496. Its totient is φ = 5904299520.

The previous prime is 21011010011. The next prime is 21011010029. The reversal of 21011010020 is 2001011012.

It is an interprime number because it is at equal distance from previous prime (21011010011) and next prime (21011010029).

It is not an unprimeable number, because it can be changed into a prime (21011010029) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 848657 + ... + 873063.

It is an arithmetic number, because the mean of its divisors is an integer number (315741888).

Almost surely, 2^21011010020 is an apocalyptic number.

21011010020 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 21011010020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30311221248).

21011010020 is an abundant number, since it is smaller than the sum of its proper divisors (39611432476).

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

21011010020 is a wasteful number, since it uses less digits than its factorization.

21011010020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24490 (or 24488 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 21011010020 its reverse (2001011012), we get a palindrome (23012021032).

The spelling of 21011010020 in words is "twenty-one billion, eleven million, ten thousand, twenty".