21078950409 has 16 divisors (see below), whose sum is σ = 34066991040. Its totient is φ = 12775121280.

The previous prime is 21078950401. The next prime is 21078950413. The reversal of 21078950409 is 90405987012.

It is not a de Polignac number, because 21078950409 - 2³ = 21078950401 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21078950401) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35486152 + ... + 35486745.

It is an arithmetic number, because the mean of its divisors is an integer number (2129186940).

Almost surely, 2^21078950409 is an apocalyptic number.

It is an amenable number.

21078950409 is a deficient number, since it is larger than the sum of its proper divisors (12988040631).

21078950409 is a wasteful number, since it uses less digits than its factorization.

21078950409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70972917 (or 70972911 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 45.

The spelling of 21078950409 in words is "twenty-one billion, seventy-eight million, nine hundred fifty thousand, four hundred nine".