205670551 has 4 divisors (see below), whose sum is σ = 206319672. Its totient is φ = 205021432.

The previous prime is 205670537. The next prime is 205670557. The reversal of 205670551 is 155076502.

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 205670551 - 2¹⁷ = 205539479 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 (205670557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 324085 + ... + 324718.

It is an arithmetic number, because the mean of its divisors is an integer number (51579918).

Almost surely, 2^205670551 is an apocalyptic number.

205670551 is a deficient number, since it is larger than the sum of its proper divisors (649121).

205670551 is an equidigital number, since it uses as much as digits as its factorization.

205670551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 649120.

The product of its (nonzero) digits is 10500, while the sum is 31.

The square root of 205670551 is about 14341.2186023364. The cubic root of 205670551 is about 590.2790511818.

The spelling of 205670551 in words is "two hundred five million, six hundred seventy thousand, five hundred fifty-one".