210101001021 has 24 divisors (see below), whose sum is σ = 330015571704. Its totient is φ = 128265154560.

The previous prime is 210101001017. The next prime is 210101001023. The reversal of 210101001021 is 120100101012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 106268828121 + 103832172900 = 325989^2 + 322230^2 .

It is not a de Polignac number, because 210101001021 - 2² = 210101001017 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 210101000994 and 210101001012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210101001023) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18551220 + ... + 18562541.

It is an arithmetic number, because the mean of its divisors is an integer number (13750648821).

Almost surely, 2^210101001021 is an apocalyptic number.

It is an amenable number.

210101001021 is a deficient number, since it is larger than the sum of its proper divisors (119914570683).

210101001021 is a wasteful number, since it uses less digits than its factorization.

210101001021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37113821 (or 37113818 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 210101001021 its reverse (120100101012), we get a palindrome (330201102033).

Subtracting from 210101001021 its reverse (120100101012), we obtain a palindrome (90000900009).

The spelling of 210101001021 in words is "two hundred ten billion, one hundred one million, one thousand, twenty-one".