61781576481 has 27 divisors (see below), whose sum is σ = 92455771161. Its totient is φ = 39753532224.

The previous prime is 61781576473. The next prime is 61781576491. The reversal of 61781576481 is 18467518716.

The square root of 61781576481 is 248559.

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

61781576481 is a `hidden beast` number, since 6 + 1 + 7 + 8 + 157 + 6 + 481 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2481534225 + 59300042256 = 49815^2 + 243516^2 .

It is not a de Polignac number, because 61781576481 - 2³ = 61781576473 is a prime.

It is a super-2 number, since 2×61781576481² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (61781576491) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 21623205 + ... + 21626061.

Almost surely, 2^61781576481 is an apocalyptic number.

61781576481 is the 248559-th square number.

61781576481 is the 124280-th centered octagonal number.

It is an amenable number.

61781576481 is a deficient number, since it is larger than the sum of its proper divisors (30674194680).

61781576481 is an frugal number, since it uses more digits than its factorization.

61781576481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5778 (or 2889 counting only the distinct ones).

The product of its digits is 2257920, while the sum is 54.

The spelling of 61781576481 in words is "sixty-one billion, seven hundred eighty-one million, five hundred seventy-six thousand, four hundred eighty-one".