21101001020021 has 16 divisors (see below), whose sum is σ = 22849311679488. Its totient is φ = 19370625096000.

The previous prime is 21101001019991. The next prime is 21101001020027. The reversal of 21101001020021 is 12002010010112.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21101001020021 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 = 21101001019984 and 21101001020011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101001020027) 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, 8041490 + ... + 10337676.

It is an arithmetic number, because the mean of its divisors is an integer number (1428081979968).

Almost surely, 2^{21101001020021} is an apocalyptic number.

It is an amenable number.

21101001020021 is a deficient number, since it is larger than the sum of its proper divisors (1748310659467).

21101001020021 is a wasteful number, since it uses less digits than its factorization.

21101001020021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2300092.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21101001020021 its reverse (12002010010112), we get a palindrome (33103011030133).

The spelling of 21101001020021 in words is "twenty-one trillion, one hundred one billion, one million, twenty thousand, twenty-one".