21010122021 has 16 divisors (see below), whose sum is σ = 32019605504. Its totient is φ = 12004215984.

The previous prime is 21010122019. The next prime is 21010122053. The reversal of 21010122021 is 12022101012.

It is not a de Polignac number, because 21010122021 - 2¹ = 21010122019 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21010121988 and 21010122006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010122011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 110256 + ... + 232758.

It is an arithmetic number, because the mean of its divisors is an integer number (2001225344).

Almost surely, 2^21010122021 is an apocalyptic number.

21010122021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21010122021 is a deficient number, since it is larger than the sum of its proper divisors (11009483483).

21010122021 is a wasteful number, since it uses less digits than its factorization.

21010122021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130680.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21010122021 its reverse (12022101012), we get a palindrome (33032223033).

The spelling of 21010122021 in words is "twenty-one billion, ten million, one hundred twenty-two thousand, twenty-one".