204945438681 has 57 divisors (see below), whose sum is σ = 321365295349. Its totient is φ = 130689844956.

The previous prime is 204945438679. The next prime is 204945438683. The reversal of 204945438681 is 186834549402.

The square root of 204945438681 is 452709.

It is a perfect power (a square), and thus also a powerful number.

204945438681 is a `hidden beast` number, since 2 + 0 + 4 + 94 + 543 + 8 + 6 + 8 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (204945438679) and next prime (204945438683).

It is not a de Polignac number, because 204945438681 - 2¹ = 204945438679 is a prime.

It is a super-2 number, since 2×204945438681² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (204945438683) by changing a digit.

It is a polite number, since it can be written in 56 ways as a sum of consecutive naturals, for example, 8910671236 + ... + 8910671258.

Almost surely, 2^204945438681 is an apocalyptic number.

204945438681 is the 452709-th square number.

204945438681 is the 226355-th centered octagonal number.

It is an amenable number.

204945438681 is a deficient number, since it is larger than the sum of its proper divisors (116419856668).

204945438681 is an frugal number, since it uses more digits than its factorization.

204945438681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100 (or 26 counting only the distinct ones).

The product of its (nonzero) digits is 6635520, while the sum is 54.

The spelling of 204945438681 in words is "two hundred four billion, nine hundred forty-five million, four hundred thirty-eight thousand, six hundred eighty-one".