138440507666 has 8 divisors (see below), whose sum is σ = 207768307824. Its totient is φ = 69184405060.

The previous prime is 138440507587. The next prime is 138440507731. The reversal of 138440507666 is 666705044831.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17919560 + ... + 17927283.

It is an arithmetic number, because the mean of its divisors is an integer number (25971038478).

Almost surely, 2^138440507666 is an apocalyptic number.

138440507666 is a deficient number, since it is larger than the sum of its proper divisors (69327800158).

138440507666 is a wasteful number, since it uses less digits than its factorization.

138440507666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35848776.

The product of its (nonzero) digits is 2903040, while the sum is 50.

The spelling of 138440507666 in words is "one hundred thirty-eight billion, four hundred forty million, five hundred seven thousand, six hundred sixty-six".