138556665 has 48 divisors (see below), whose sum is σ = 259983360. Its totient is φ = 67858560.

The previous prime is 138556661. The next prime is 138556697. The reversal of 138556665 is 566655831.

It is not a de Polignac number, because 138556665 - 2² = 138556661 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 138556665.

It is not an unprimeable number, because it can be changed into a prime (138556661) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 139320 + ... + 140310.

It is an arithmetic number, because the mean of its divisors is an integer number (5416320).

Almost surely, 2^138556665 is an apocalyptic number.

138556665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

138556665 is a deficient number, since it is larger than the sum of its proper divisors (121426695).

138556665 is a wasteful number, since it uses less digits than its factorization.

138556665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1254 (or 1251 counting only the distinct ones).

The product of its digits is 648000, while the sum is 45.

The square root of 138556665 is about 11771.0095149057. The cubic root of 138556665 is about 517.4588359052.

The spelling of 138556665 in words is "one hundred thirty-eight million, five hundred fifty-six thousand, six hundred sixty-five".