21020112021 has 16 divisors (see below), whose sum is σ = 29280332160. Its totient is φ = 13396219200.

The previous prime is 21020112007. The next prime is 21020112031. The reversal of 21020112021 is 12021102012.

It is not a de Polignac number, because 21020112021 - 2²⁵ = 20986557589 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21020111988 and 21020112006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020112031) 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, 1187305 + ... + 1204878.

It is an arithmetic number, because the mean of its divisors is an integer number (1830020760).

Almost surely, 2^21020112021 is an apocalyptic number.

It is an amenable number.

21020112021 is a deficient number, since it is larger than the sum of its proper divisors (8260220139).

21020112021 is a wasteful number, since it uses less digits than its factorization.

21020112021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2392316.

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

Adding to 21020112021 its reverse (12021102012), we get a palindrome (33041214033).

It can be divided in two parts, 210201 and 12021, that added together give a palindrome (222222).

The spelling of 21020112021 in words is "twenty-one billion, twenty million, one hundred twelve thousand, twenty-one".