204194640129561 has 63 divisors (see below), whose sum is σ = 308205770199663. Its totient is φ = 135222566160240.

The previous prime is 204194640129553. The next prime is 204194640129593. The reversal of 204194640129561 is 165921046491402.

The square root of 204194640129561 is 14289669.

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

204194640129561 is a `hidden beast` number, since 2 + 0 + 4 + 1 + 9 + 4 + 64 + 0 + 12 + 9 + 561 = 666.

It can be written as a sum of positive squares in only one way, i.e., 59852581238025 + 144342058891536 = 7736445^2 + 12014244^2 .

It is not a de Polignac number, because 204194640129561 - 2³ = 204194640129553 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 204194640129498 and 204194640129507.

It is not an unprimeable number, because it can be changed into a prime (204194640129551) by changing a digit.

It is a polite number, since it can be written in 62 ways as a sum of consecutive naturals, for example, 60573905206 + ... + 60573908576.

Almost surely, 2^{204194640129561} is an apocalyptic number.

204194640129561 is the 14289669-th square number.

204194640129561 is the 7144835-th centered octagonal number.

It is an amenable number.

204194640129561 is a deficient number, since it is larger than the sum of its proper divisors (104011130070102).

204194640129561 is an frugal number, since it uses more digits than its factorization.

204194640129561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7074 (or 3531 counting only the distinct ones).

The product of its (nonzero) digits is 3732480, while the sum is 54.

The spelling of 204194640129561 in words is "two hundred four trillion, one hundred ninety-four billion, six hundred forty million, one hundred twenty-nine thousand, five hundred sixty-one".