21345180905 has 4 divisors (see below), whose sum is σ = 25614217092. Its totient is φ = 17076144720.

The previous prime is 21345180881. The next prime is 21345180919. The reversal of 21345180905 is 50908154312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4522831504 + 16822349401 = 67252^2 + 129701^2 .

It is not a de Polignac number, because 21345180905 - 2²⁴ = 21328403689 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2134518086 + ... + 2134518095.

It is an arithmetic number, because the mean of its divisors is an integer number (6403554273).

Almost surely, 2^21345180905 is an apocalyptic number.

It is an amenable number.

21345180905 is a deficient number, since it is larger than the sum of its proper divisors (4269036187).

21345180905 is an equidigital number, since it uses as much as digits as its factorization.

21345180905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4269036186.

The product of its (nonzero) digits is 43200, while the sum is 38.

The spelling of 21345180905 in words is "twenty-one billion, three hundred forty-five million, one hundred eighty thousand, nine hundred five".