61540902729601 has 3 divisors (see below), whose sum is σ = 61540910574403. Its totient is φ = 61540894884800.

The previous prime is 61540902729571. The next prime is 61540902729629. The reversal of 61540902729601 is 10692720904516.

The square root of 61540902729601 is 7844801.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 1270851201 + 61539631878400 = 35649^2 + 7844720^2 .

It is not a de Polignac number, because 61540902729601 - 2⁵ = 61540902729569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61540902729641) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 3922401 + ... + 11767201.

Almost surely, 2^{61540902729601} is an apocalyptic number.

61540902729601 is the 7844801-st square number.

61540902729601 is the 3922401-st centered octagonal number.

It is an amenable number.

61540902729601 is a deficient number, since it is larger than the sum of its proper divisors (7844802).

61540902729601 is an frugal number, since it uses more digits than its factorization.

61540902729601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15689602 (or 7844801 counting only the distinct ones).

The product of its (nonzero) digits is 1632960, while the sum is 52.

The spelling of 61540902729601 in words is "sixty-one trillion, five hundred forty billion, nine hundred two million, seven hundred twenty-nine thousand, six hundred one".