66617761 has 4 divisors (see below), whose sum is σ = 76134592. Its totient is φ = 57100932.

The previous prime is 66617737. The next prime is 66617773. The reversal of 66617761 is 16771666.

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, and also an emirpimes, since its reverse is a distinct semiprime: 16771666 = 2 ⋅8385833.

It is not a de Polignac number, because 66617761 - 2⁷ = 66617633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66617261) 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, 4758405 + ... + 4758418.

It is an arithmetic number, because the mean of its divisors is an integer number (19033648).

Almost surely, 2^66617761 is an apocalyptic number.

It is an amenable number.

66617761 is a deficient number, since it is larger than the sum of its proper divisors (9516831).

66617761 is an equidigital number, since it uses as much as digits as its factorization.

66617761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9516830.

The product of its digits is 63504, while the sum is 40.

The square root of 66617761 is about 8161.9704116102. The cubic root of 66617761 is about 405.3809574019.

The spelling of 66617761 in words is "sixty-six million, six hundred seventeen thousand, seven hundred sixty-one".