21011103309 has 64 divisors (see below), whose sum is σ = 33741840384. Its totient is φ = 11380455936.

The previous prime is 21011103299. The next prime is 21011103331. The reversal of 21011103309 is 90330111012.

It is not a de Polignac number, because 21011103309 - 2⁵ = 21011103277 is a prime.

It is a super-2 number, since 2×21011103309² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011103349) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4705612 + ... + 4710074.

It is an arithmetic number, because the mean of its divisors is an integer number (527216256).

Almost surely, 2^21011103309 is an apocalyptic number.

It is an amenable number.

21011103309 is a deficient number, since it is larger than the sum of its proper divisors (12730737075).

21011103309 is a wasteful number, since it uses less digits than its factorization.

21011103309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4666.

The product of its (nonzero) digits is 162, while the sum is 21.

The spelling of 21011103309 in words is "twenty-one billion, eleven million, one hundred three thousand, three hundred nine".