205454621664451 has 4 divisors (see below), whose sum is σ = 205667087665072. Its totient is φ = 205242155663832.

The previous prime is 205454621664443. The next prime is 205454621664473. The reversal of 205454621664451 is 154466126454502.

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 205454621664451 - 2³ = 205454621664443 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 205454621664392 and 205454621664401.

It is not an unprimeable number, because it can be changed into a prime (205454621664421) 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, 106232998860 + ... + 106233000793.

It is an arithmetic number, because the mean of its divisors is an integer number (51416771916268).

Almost surely, 2^{205454621664451} is an apocalyptic number.

205454621664451 is a deficient number, since it is larger than the sum of its proper divisors (212466000621).

205454621664451 is an equidigital number, since it uses as much as digits as its factorization.

205454621664451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212466000620.

The product of its (nonzero) digits is 27648000, while the sum is 55.

The spelling of 205454621664451 in words is "two hundred five trillion, four hundred fifty-four billion, six hundred twenty-one million, six hundred sixty-four thousand, four hundred fifty-one".