138407661 has 24 divisors (see below), whose sum is σ = 229245120. Its totient is φ = 78826176.

The previous prime is 138407627. The next prime is 138407663. The reversal of 138407661 is 166704831.

It is not a de Polignac number, because 138407661 - 2¹⁹ = 137883373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138407663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16210 + ... + 23228.

It is an arithmetic number, because the mean of its divisors is an integer number (9551880).

Almost surely, 2^138407661 is an apocalyptic number.

It is an amenable number.

138407661 is a deficient number, since it is larger than the sum of its proper divisors (90837459).

138407661 is a wasteful number, since it uses less digits than its factorization.

138407661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7345 (or 7342 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 138407661 is about 11764.6785336447. The cubic root of 138407661 is about 517.2732774264.

The spelling of 138407661 in words is "one hundred thirty-eight million, four hundred seven thousand, six hundred sixty-one".