205019640 has 256 divisors, whose sum is σ = 799027200. Its totient is φ = 45785088.

The previous prime is 205019623. The next prime is 205019651. The reversal of 205019640 is 46910502.

205019640 is a `hidden beast` number, since 2 + 0 + 5 + 0 + 19 + 640 = 666.

205019640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 355032 + ... + 355608.

It is an arithmetic number, because the mean of its divisors is an integer number (3121200).

Almost surely, 2^205019640 is an apocalyptic number.

205019640 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 205019640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (399513600).

205019640 is an abundant number, since it is smaller than the sum of its proper divisors (594007560).

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

205019640 is a wasteful number, since it uses less digits than its factorization.

205019640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 651 (or 641 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 205019640 is about 14318.5069054004. The cubic root of 205019640 is about 589.6556834247.

The spelling of 205019640 in words is "two hundred five million, nineteen thousand, six hundred forty".