205454742279 has 4 divisors (see below), whose sum is σ = 273939656376. Its totient is φ = 136969828184.

The previous prime is 205454742257. The next prime is 205454742299. The reversal of 205454742279 is 972247454502.

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 205454742279 - 2¹² = 205454738183 is a prime.

It is a super-2 number, since 2×205454742279² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205454742209) 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, 34242457044 + ... + 34242457049.

It is an arithmetic number, because the mean of its divisors is an integer number (68484914094).

Almost surely, 2^205454742279 is an apocalyptic number.

205454742279 is a deficient number, since it is larger than the sum of its proper divisors (68484914097).

205454742279 is an equidigital number, since it uses as much as digits as its factorization.

205454742279 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68484914096.

The product of its (nonzero) digits is 5644800, while the sum is 51.

The spelling of 205454742279 in words is "two hundred five billion, four hundred fifty-four million, seven hundred forty-two thousand, two hundred seventy-nine".