21779259891395 has 4 divisors (see below), whose sum is σ = 26135111869680. Its totient is φ = 17423407913112.

The previous prime is 21779259891383. The next prime is 21779259891409. The reversal of 21779259891395 is 59319895297712.

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

It is a cyclic number.

It is not a de Polignac number, because 21779259891395 - 2⁶ = 21779259891331 is a prime.

It is a super-2 number, since 2×21779259891395² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2177925989135 + ... + 2177925989144.

It is an arithmetic number, because the mean of its divisors is an integer number (6533777967420).

Almost surely, 2^{21779259891395} is an apocalyptic number.

21779259891395 is a deficient number, since it is larger than the sum of its proper divisors (4355851978285).

21779259891395 is an equidigital number, since it uses as much as digits as its factorization.

21779259891395 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4355851978284.

The product of its digits is 771573600, while the sum is 77.

The spelling of 21779259891395 in words is "twenty-one trillion, seven hundred seventy-nine billion, two hundred fifty-nine million, eight hundred ninety-one thousand, three hundred ninety-five".