205428217017251 has 4 divisors (see below), whose sum is σ = 205428605803872. Its totient is φ = 205427828230632.

The previous prime is 205428217017209. The next prime is 205428217017277. The reversal of 205428217017251 is 152710712824502.

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 205428217017251 - 2³⁴ = 205411037148067 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 205428217017196 and 205428217017205.

It is not an unprimeable number, because it can be changed into a prime (205428217010251) 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, 193599656 + ... + 194657861.

It is an arithmetic number, because the mean of its divisors is an integer number (51357151450968).

Almost surely, 2^{205428217017251} is an apocalyptic number.

205428217017251 is a deficient number, since it is larger than the sum of its proper divisors (388786621).

205428217017251 is an equidigital number, since it uses as much as digits as its factorization.

205428217017251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388786620.

The product of its (nonzero) digits is 627200, while the sum is 47.

The spelling of 205428217017251 in words is "two hundred five trillion, four hundred twenty-eight billion, two hundred seventeen million, seventeen thousand, two hundred fifty-one".