205778664 has 384 divisors, whose sum is σ = 768096000. Its totient is φ = 49641984.

The previous prime is 205778627. The next prime is 205778669. The reversal of 205778664 is 466877502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205778669) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 7095802 + ... + 7095830.

It is an arithmetic number, because the mean of its divisors is an integer number (2000250).

Almost surely, 2^205778664 is an apocalyptic number.

205778664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 205778664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (384048000).

205778664 is an abundant number, since it is smaller than the sum of its proper divisors (562317336).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

205778664 is a wasteful number, since it uses less digits than its factorization.

205778664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102 (or 73 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 45.

The square root of 205778664 is about 14344.9874172130. The cubic root of 205778664 is about 590.3824619683.

It can be divided in two parts, 20577 and 8664, that added together give a square (29241 = 171²).

The spelling of 205778664 in words is "two hundred five million, seven hundred seventy-eight thousand, six hundred sixty-four".