61663028361561 has 45 divisors (see below), whose sum is σ = 101250446522533. Its totient is φ = 37371061185480.

The previous prime is 61663028361559. The next prime is 61663028361601. The reversal of 61663028361561 is 16516382036616.

The square root of 61663028361561 is 7852581.

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

61663028361561 is a `hidden beast` number, since 6 + 16 + 6 + 3 + 0 + 2 + 8 + 3 + 61 + 561 = 666.

It is not a de Polignac number, because 61663028361561 - 2¹ = 61663028361559 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 61663028361498 and 61663028361507.

It is not an unprimeable number, because it can be changed into a prime (61663028361551) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 777365860 + ... + 777445178.

Almost surely, 2^{61663028361561} is an apocalyptic number.

61663028361561 is the 7852581-st square number.

61663028361561 is the 3926291-st centered octagonal number.

It is an amenable number.

61663028361561 is a deficient number, since it is larger than the sum of its proper divisors (39587418160972).

61663028361561 is an frugal number, since it uses more digits than its factorization.

61663028361561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158672 (or 79333 counting only the distinct ones).

The product of its (nonzero) digits is 5598720, while the sum is 54.

The spelling of 61663028361561 in words is "sixty-one trillion, six hundred sixty-three billion, twenty-eight million, three hundred sixty-one thousand, five hundred sixty-one".