21013115009 has 4 divisors (see below), whose sum is σ = 21075468804. Its totient is φ = 20950761216.

The previous prime is 21013115003. The next prime is 21013115033. The reversal of 21013115009 is 90051131012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10506865009 + 10506250000 = 102503^2 + 102500^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21013115009 is a prime.

It is a super-2 number, since 2×21013115009² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21013115003) 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, 31176392 + ... + 31177065.

It is an arithmetic number, because the mean of its divisors is an integer number (5268867201).

Almost surely, 2^21013115009 is an apocalyptic number.

It is an amenable number.

21013115009 is a deficient number, since it is larger than the sum of its proper divisors (62353795).

21013115009 is an equidigital number, since it uses as much as digits as its factorization.

21013115009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62353794.

The product of its (nonzero) digits is 270, while the sum is 23.

The spelling of 21013115009 in words is "twenty-one billion, thirteen million, one hundred fifteen thousand, nine".