21958941805 has 4 divisors (see below), whose sum is σ = 26350730172. Its totient is φ = 17567153440.

The previous prime is 21958941779. The next prime is 21958941811. The reversal of 21958941805 is 50814985912.

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 2389449924 + 19569491881 = 48882^2 + 139891^2 .

It is not a de Polignac number, because 21958941805 - 2⁵ = 21958941773 is a prime.

It is a Duffinian number.

It is a congruent 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, 2195894176 + ... + 2195894185.

It is an arithmetic number, because the mean of its divisors is an integer number (6587682543).

Almost surely, 2^21958941805 is an apocalyptic number.

It is an amenable number.

21958941805 is a deficient number, since it is larger than the sum of its proper divisors (4391788367).

21958941805 is an equidigital number, since it uses as much as digits as its factorization.

21958941805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4391788366.

The product of its (nonzero) digits is 1036800, while the sum is 52.

The spelling of 21958941805 in words is "twenty-one billion, nine hundred fifty-eight million, nine hundred forty-one thousand, eight hundred five".