205208640 has 672 divisors, whose sum is σ = 931956480. Its totient is φ = 41803776.

The previous prime is 205208639. The next prime is 205208657. The reversal of 205208640 is 46802502.

205208640 is a `hidden beast` number, since 20 + 520 + 86 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

It is a super-2 number, since 2×205208640² = 84221171861299200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 7076146 + ... + 7076174.

It is an arithmetic number, because the mean of its divisors is an integer number (1386840).

Almost surely, 2^205208640 is an apocalyptic number.

205208640 is a gapful number since it is divisible by the number (20) 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 205208640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (465978240).

205208640 is an abundant number, since it is smaller than the sum of its proper divisors (726747840).

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

205208640 is a wasteful number, since it uses less digits than its factorization.

205208640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81 (or 59 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 205208640 is about 14325.1052352156. The cubic root of 205208640 is about 589.8368216741.

The spelling of 205208640 in words is "two hundred five million, two hundred eight thousand, six hundred forty".