61511712661 has 4 divisors (see below), whose sum is σ = 70299100192. Its totient is φ = 52724325132.

The previous prime is 61511712649. The next prime is 61511712679. The reversal of 61511712661 is 16621711516.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61511712661 - 2⁷ = 61511712533 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 61511712661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61511712761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4393693755 + ... + 4393693768.

It is an arithmetic number, because the mean of its divisors is an integer number (17574775048).

Almost surely, 2^61511712661 is an apocalyptic number.

It is an amenable number.

61511712661 is a deficient number, since it is larger than the sum of its proper divisors (8787387531).

61511712661 is an equidigital number, since it uses as much as digits as its factorization.

61511712661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8787387530.

The product of its digits is 15120, while the sum is 37.

The spelling of 61511712661 in words is "sixty-one billion, five hundred eleven million, seven hundred twelve thousand, six hundred sixty-one".