21065110409 has 4 divisors (see below), whose sum is σ = 24074411904. Its totient is φ = 18055808916.

The previous prime is 21065110379. The next prime is 21065110457. The reversal of 21065110409 is 90401156012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21065110409 - 2²⁸ = 20796674953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21065110309) 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, 1504650737 + ... + 1504650750.

It is an arithmetic number, because the mean of its divisors is an integer number (6018602976).

Almost surely, 2^21065110409 is an apocalyptic number.

It is an amenable number.

21065110409 is a deficient number, since it is larger than the sum of its proper divisors (3009301495).

21065110409 is an equidigital number, since it uses as much as digits as its factorization.

21065110409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3009301494.

The product of its (nonzero) digits is 2160, while the sum is 29.

The spelling of 21065110409 in words is "twenty-one billion, sixty-five million, one hundred ten thousand, four hundred nine".