204155640 has 320 divisors, whose sum is σ = 764739360. Its totient is φ = 48522240.

The previous prime is 204155599. The next prime is 204155641. The reversal of 204155640 is 46551402.

204155640 is a `hidden beast` number, since 2 + 0 + 4 + 15 + 5 + 640 = 666.

204155640 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 not an unprimeable number, because it can be changed into a prime (204155641) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1558375 + ... + 1558505.

Almost surely, 2^204155640 is an apocalyptic number.

204155640 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 204155640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (382369680).

204155640 is an abundant number, since it is smaller than the sum of its proper divisors (560583720).

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

204155640 is a wasteful number, since it uses less digits than its factorization.

204155640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204 (or 191 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 204155640 is about 14288.3043080696. The cubic root of 204155640 is about 588.8262021534.

The spelling of 204155640 in words is "two hundred four million, one hundred fifty-five thousand, six hundred forty".