6661000138 has 24 divisors (see below), whose sum is σ = 11083104396. Its totient is φ = 2999318400.

The previous prime is 6661000133. The next prime is 6661000139. The reversal of 6661000138 is 8310001666.

It can be written as a sum of positive squares in 6 ways, for example, as 646532329 + 6014467809 = 25427^2 + 77553^2 .

It is not an unprimeable number, because it can be changed into a prime (6661000133) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 226473 + ... + 254188.

Almost surely, 2^6661000138 is an apocalyptic number.

6661000138 is a deficient number, since it is larger than the sum of its proper divisors (4422104258).

6661000138 is a wasteful number, since it uses less digits than its factorization.

6661000138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 480730 (or 480717 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 6661000138 is about 81614.9504563962. The cubic root of 6661000138 is about 1881.5386658461.

The spelling of 6661000138 in words is "six billion, six hundred sixty-one million, one hundred thirty-eight", and thus it is an aban number.