21120001109 has 6 divisors (see below), whose sum is σ = 21237363810. Its totient is φ = 21003283440.

The previous prime is 21120001103. The next prime is 21120001127. The reversal of 21120001109 is 90110002112.

It can be written as a sum of positive squares in 3 ways, for example, as 930433009 + 20189568100 = 30503^2 + 142090^2 .

It is not a de Polignac number, because 21120001109 - 2⁴ = 21120001093 is a prime.

It is a super-2 number, since 2×21120001109² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120001103) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 289574 + ... + 355095.

It is an arithmetic number, because the mean of its divisors is an integer number (3539560635).

Almost surely, 2^21120001109 is an apocalyptic number.

It is an amenable number.

21120001109 is a deficient number, since it is larger than the sum of its proper divisors (117362701).

21120001109 is an frugal number, since it uses more digits than its factorization.

21120001109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 645031 (or 644850 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 17.

The spelling of 21120001109 in words is "twenty-one billion, one hundred twenty million, one thousand, one hundred nine".