21020013011 has 4 divisors (see below), whose sum is σ = 21107233224. Its totient is φ = 20932792800.

The previous prime is 21020012999. The next prime is 21020013023. The reversal of 21020013011 is 11031002012.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21020012999) and next prime (21020013023).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21020013011 is a prime.

It is a super-2 number, since 2×21020013011² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21020012983 and 21020013001.

It is not an unprimeable number, because it can be changed into a prime (21020013071) 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, 43609745 + ... + 43610226.

It is an arithmetic number, because the mean of its divisors is an integer number (5276808306).

Almost surely, 2^21020013011 is an apocalyptic number.

21020013011 is a deficient number, since it is larger than the sum of its proper divisors (87220213).

21020013011 is an equidigital number, since it uses as much as digits as its factorization.

21020013011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87220212.

The product of its (nonzero) digits is 12, while the sum is 11.

Adding to 21020013011 its reverse (11031002012), we get a palindrome (32051015023).

It can be divided in two parts, 2102001 and 3011, that added together give a palindrome (2105012).

The spelling of 21020013011 in words is "twenty-one billion, twenty million, thirteen thousand, eleven".