61666772739 has 16 divisors (see below), whose sum is σ = 96596903424. Its totient is φ = 34498893600.

The previous prime is 61666772711. The next prime is 61666772767. The reversal of 61666772739 is 93727766616.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (61666772711) and next prime (61666772767).

It is not a de Polignac number, because 61666772739 - 2¹¹ = 61666770691 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61666772239) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 71872267 + ... + 71873124.

It is an arithmetic number, because the mean of its divisors is an integer number (6037306464).

Almost surely, 2^61666772739 is an apocalyptic number.

61666772739 is a deficient number, since it is larger than the sum of its proper divisors (34930130685).

61666772739 is a wasteful number, since it uses less digits than its factorization.

61666772739 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143745418.

The product of its digits is 24004512, while the sum is 60.

The spelling of 61666772739 in words is "sixty-one billion, six hundred sixty-six million, seven hundred seventy-two thousand, seven hundred thirty-nine".