6661064077 has 4 divisors (see below), whose sum is σ = 6661551996. Its totient is φ = 6660576160.

The previous prime is 6661063999. The next prime is 6661064101. The reversal of 6661064077 is 7704601666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7704601666 = 2 ⋅3852300833.

It can be written as a sum of positive squares in 2 ways, for example, as 977562756 + 5683501321 = 31266^2 + 75389^2 .

It is a cyclic number.

It is not a de Polignac number, because 6661064077 - 2¹⁵ = 6661031309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6661064677) 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, 222874 + ... + 250987.

It is an arithmetic number, because the mean of its divisors is an integer number (1665387999).

Almost surely, 2^6661064077 is an apocalyptic number.

It is an amenable number.

6661064077 is a deficient number, since it is larger than the sum of its proper divisors (487919).

6661064077 is a wasteful number, since it uses less digits than its factorization.

6661064077 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 487918.

The product of its (nonzero) digits is 254016, while the sum is 43.

The square root of 6661064077 is about 81615.3421667765. The cubic root of 6661064077 is about 1881.5446861290.

The spelling of 6661064077 in words is "six billion, six hundred sixty-one million, sixty-four thousand, seventy-seven".