205978240 has 128 divisors (see below), whose sum is σ = 558633600. Its totient is φ = 71995392.

The previous prime is 205978231. The next prime is 205978249. The reversal of 205978240 is 42879502.

It is an interprime number because it is at equal distance from previous prime (205978231) and next prime (205978249).

It is a tau number, because it is divible by the number of its divisors (128).

It is a self number, because there is not a number n which added to its sum of digits gives 205978240.

It is not an unprimeable number, because it can be changed into a prime (205978249) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 157429 + ... + 158731.

It is an arithmetic number, because the mean of its divisors is an integer number (4364325).

Almost surely, 2^205978240 is an apocalyptic number.

205978240 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 205978240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (279316800).

205978240 is an abundant number, since it is smaller than the sum of its proper divisors (352655360).

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

205978240 is a wasteful number, since it uses less digits than its factorization.

205978240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1354 (or 1342 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 37.

The square root of 205978240 is about 14351.9420288684. The cubic root of 205978240 is about 590.5732626032.

The spelling of 205978240 in words is "two hundred five million, nine hundred seventy-eight thousand, two hundred forty".