21952278905 has 4 divisors (see below), whose sum is σ = 26342734692. Its totient is φ = 17561823120.

The previous prime is 21952278889. The next prime is 21952278913. The reversal of 21952278905 is 50987225912.

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 2796611689 + 19155667216 = 52883^2 + 138404^2 .

It is not a de Polignac number, because 21952278905 - 2⁴ = 21952278889 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, 2195227886 + ... + 2195227895.

It is an arithmetic number, because the mean of its divisors is an integer number (6585683673).

Almost surely, 2^21952278905 is an apocalyptic number.

It is an amenable number.

21952278905 is a deficient number, since it is larger than the sum of its proper divisors (4390455787).

21952278905 is an equidigital number, since it uses as much as digits as its factorization.

21952278905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4390455786.

The product of its (nonzero) digits is 907200, while the sum is 50.

The spelling of 21952278905 in words is "twenty-one billion, nine hundred fifty-two million, two hundred seventy-eight thousand, nine hundred five".