66666697040 has 20 divisors (see below), whose sum is σ = 155000070804. Its totient is φ = 26666678784.

The previous prime is 66666697037. The next prime is 66666697049. The reversal of 66666697040 is 4079666666.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 10817664064 + 55849032976 = 104008^2 + 236324^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66666697049) 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, 416666777 + ... + 416666936.

Almost surely, 2^66666697040 is an apocalyptic number.

It is an amenable number.

66666697040 is an abundant number, since it is smaller than the sum of its proper divisors (88333373764).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66666697040 is a wasteful number, since it uses less digits than its factorization.

66666697040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 833333726 (or 833333720 counting only the distinct ones).

The product of its (nonzero) digits is 11757312, while the sum is 56.

The spelling of 66666697040 in words is "sixty-six billion, six hundred sixty-six million, six hundred ninety-seven thousand, forty".