21086438109 has 32 divisors (see below), whose sum is σ = 30801984000. Its totient is φ = 12725294400.

The previous prime is 21086438099. The next prime is 21086438161. The reversal of 21086438109 is 90183468012.

It is not a de Polignac number, because 21086438109 - 2⁹ = 21086437597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21086438179) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9006279 + ... + 9008619.

It is an arithmetic number, because the mean of its divisors is an integer number (962562000).

Almost surely, 2^21086438109 is an apocalyptic number.

It is an amenable number.

21086438109 is a deficient number, since it is larger than the sum of its proper divisors (9715545891).

21086438109 is a wasteful number, since it uses less digits than its factorization.

21086438109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3401.

The product of its (nonzero) digits is 82944, while the sum is 42.

The spelling of 21086438109 in words is "twenty-one billion, eighty-six million, four hundred thirty-eight thousand, one hundred nine".