61658719561 has 4 divisors (see below), whose sum is σ = 61661082132. Its totient is φ = 61656356992.

The previous prime is 61658719553. The next prime is 61658719579. The reversal of 61658719561 is 16591785616.

61658719561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16264155961 + 45394563600 = 127531^2 + 213060^2 .

It is a cyclic number.

It is not a de Polignac number, because 61658719561 - 2³ = 61658719553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61658719261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1141696 + ... + 1194481.

It is an arithmetic number, because the mean of its divisors is an integer number (15415270533).

Almost surely, 2^61658719561 is an apocalyptic number.

It is an amenable number.

61658719561 is a deficient number, since it is larger than the sum of its proper divisors (2362571).

61658719561 is a wasteful number, since it uses less digits than its factorization.

61658719561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2362570.

The product of its digits is 2721600, while the sum is 55.

The spelling of 61658719561 in words is "sixty-one billion, six hundred fifty-eight million, seven hundred nineteen thousand, five hundred sixty-one".