205661504 has 42 divisors (see below), whose sum is σ = 422778174. Its totient is φ = 99258880.

The previous prime is 205661479. The next prime is 205661507. The reversal of 205661504 is 405166502.

It can be written as a sum of positive squares in 3 ways, for example, as 74787904 + 130873600 = 8648^2 + 11440^2 .

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205661507) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 51914 + ... + 55734.

It is an arithmetic number, because the mean of its divisors is an integer number (10066147).

Almost surely, 2^205661504 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 205661504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (211389087).

205661504 is an abundant number, since it is smaller than the sum of its proper divisors (217116670).

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

205661504 is an equidigital number, since it uses as much as digits as its factorization.

205661504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3891 (or 3852 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 205661504 is about 14340.9031793677. The cubic root of 205661504 is about 590.2703960245.

The spelling of 205661504 in words is "two hundred five million, six hundred sixty-one thousand, five hundred four".