21020032021021 has 12 divisors (see below), whose sum is σ = 23333422351932. Its totient is φ = 18919920800000.

The previous prime is 21020032021013. The next prime is 21020032021081. The reversal of 21020032021021 is 12012023002012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20613969948121 + 406062072900 = 4540261^2 + 637230^2 .

It is not a de Polignac number, because 21020032021021 - 2³ = 21020032021013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21020032020986 and 21020032021004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020032021081) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 859984180 + ... + 860008621.

It is an arithmetic number, because the mean of its divisors is an integer number (1944451862661).

Almost surely, 2^{21020032021021} is an apocalyptic number.

It is an amenable number.

21020032021021 is a deficient number, since it is larger than the sum of its proper divisors (2313390330911).

21020032021021 is a wasteful number, since it uses less digits than its factorization.

21020032021021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1719992924 (or 1719992913 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21020032021021 its reverse (12012023002012), we get a palindrome (33032055023033).

The spelling of 21020032021021 in words is "twenty-one trillion, twenty billion, thirty-two million, twenty-one thousand, twenty-one".