205005379861 has 4 divisors (see below), whose sum is σ = 205006424224. Its totient is φ = 205004335500.

The previous prime is 205005379853. The next prime is 205005379879. The reversal of 205005379861 is 168973500502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 205005379861 - 2³ = 205005379853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205005370861) 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, 129105 + ... + 653206.

It is an arithmetic number, because the mean of its divisors is an integer number (51251606056).

Almost surely, 2^205005379861 is an apocalyptic number.

It is an amenable number.

205005379861 is a deficient number, since it is larger than the sum of its proper divisors (1044363).

205005379861 is an equidigital number, since it uses as much as digits as its factorization.

205005379861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1044362.

The product of its (nonzero) digits is 453600, while the sum is 46.

The spelling of 205005379861 in words is "two hundred five billion, five million, three hundred seventy-nine thousand, eight hundred sixty-one".