660406240400777 has 4 divisors (see below), whose sum is σ = 711206720431620. Its totient is φ = 609605760369936.

The previous prime is 660406240400749. The next prime is 660406240400801. The reversal of 660406240400777 is 777004042604066.

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 320336828977936 + 340069411422841 = 17897956^2 + 18440971^2 .

It is a cyclic number.

It is not a de Polignac number, because 660406240400777 - 2³⁶ = 660337520924041 is a prime.

It is a super-2 number, since 2×660406240400777² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660406240430777) 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, 25400240015402 + ... + 25400240015427.

It is an arithmetic number, because the mean of its divisors is an integer number (177801680107905).

Almost surely, 2^{660406240400777} is an apocalyptic number.

It is an amenable number.

660406240400777 is a deficient number, since it is larger than the sum of its proper divisors (50800480030843).

660406240400777 is a wasteful number, since it uses less digits than its factorization.

660406240400777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50800480030842.

The product of its (nonzero) digits is 9483264, while the sum is 53.

The spelling of 660406240400777 in words is "six hundred sixty trillion, four hundred six billion, two hundred forty million, four hundred thousand, seven hundred seventy-seven".