21201101020 has 48 divisors (see below), whose sum is σ = 48879236448. Its totient is φ = 7660373760.

The previous prime is 21201101003. The next prime is 21201101083. The reversal of 21201101020 is 2010110212.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21201100988 and 21201101006.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 272367 + ... + 341446.

It is an arithmetic number, because the mean of its divisors is an integer number (1018317426).

Almost surely, 2^21201101020 is an apocalyptic number.

21201101020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21201101020 is an abundant number, since it is smaller than the sum of its proper divisors (27678135428).

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

21201101020 is a wasteful number, since it uses less digits than its factorization.

21201101020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 613990 (or 613988 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21201101020 its reverse (2010110212), we get a palindrome (23211211232).

It can be divided in two parts, 21201 and 101020, that added together give a palindrome (122221).

The spelling of 21201101020 in words is "twenty-one billion, two hundred one million, one hundred one thousand, twenty".