205551623 has 4 divisors (see below), whose sum is σ = 212639640. Its totient is φ = 198463608.

The previous prime is 205551611. The next prime is 205551629. The reversal of 205551623 is 326155502.

It is a happy number.

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 205551623 - 2⁶ = 205551559 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 7087987 = 205551623 / (2 + 0 + 5 + 5 + 5 + 1 + 6 + 2 + 3).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205551629) 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, 3543965 + ... + 3544022.

It is an arithmetic number, because the mean of its divisors is an integer number (53159910).

Almost surely, 2^205551623 is an apocalyptic number.

205551623 is a deficient number, since it is larger than the sum of its proper divisors (7088017).

205551623 is an equidigital number, since it uses as much as digits as its factorization.

205551623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7088016.

The product of its (nonzero) digits is 9000, while the sum is 29.

The square root of 205551623 is about 14337.0716326592. The cubic root of 205551623 is about 590.1652539106.

The spelling of 205551623 in words is "two hundred five million, five hundred fifty-one thousand, six hundred twenty-three".