21002111131021 has 4 divisors (see below), whose sum is σ = 21101647202944. Its totient is φ = 20902575059100.

The previous prime is 21002111130971. The next prime is 21002111131049. The reversal of 21002111131021 is 12013111120012.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21002111131021 - 2¹⁷ = 21002110999949 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002111130986 and 21002111131004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002111111021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49768035645 + ... + 49768036066.

It is an arithmetic number, because the mean of its divisors is an integer number (5275411800736).

Almost surely, 2^{21002111131021} is an apocalyptic number.

It is an amenable number.

21002111131021 is a deficient number, since it is larger than the sum of its proper divisors (99536071923).

21002111131021 is an equidigital number, since it uses as much as digits as its factorization.

21002111131021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99536071922.

The product of its (nonzero) digits is 24, while the sum is 16.

Adding to 21002111131021 its reverse (12013111120012), we get a palindrome (33015222251033).

The spelling of 21002111131021 in words is "twenty-one trillion, two billion, one hundred eleven million, one hundred thirty-one thousand, twenty-one".