21002101021 has 32 divisors (see below), whose sum is σ = 24397915392. Its totient is φ = 17889231360.

The previous prime is 21002100997. The next prime is 21002101033. The reversal of 21002101021 is 12010120012.

It is not a de Polignac number, because 21002101021 - 2⁵ = 21002100989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002100989 and 21002101007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002102021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14655321 + ... + 14656753.

It is an arithmetic number, because the mean of its divisors is an integer number (762434856).

Almost surely, 2^21002101021 is an apocalyptic number.

It is an amenable number.

21002101021 is a deficient number, since it is larger than the sum of its proper divisors (3395814371).

21002101021 is a wasteful number, since it uses less digits than its factorization.

21002101021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2613.

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

Adding to 21002101021 its reverse (12010120012), we get a palindrome (33012221033).

The spelling of 21002101021 in words is "twenty-one billion, two million, one hundred one thousand, twenty-one".