138583721 has 8 divisors (see below), whose sum is σ = 144460800. Its totient is φ = 132779920.

The previous prime is 138583703. The next prime is 138583729. The reversal of 138583721 is 127385831.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 138583721 - 2⁶ = 138583657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138583729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14441 + ... + 22038.

It is an arithmetic number, because the mean of its divisors is an integer number (18057600).

Almost surely, 2^138583721 is an apocalyptic number.

It is an amenable number.

138583721 is a deficient number, since it is larger than the sum of its proper divisors (5877079).

138583721 is a wasteful number, since it uses less digits than its factorization.

138583721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36639.

The product of its digits is 40320, while the sum is 38.

The square root of 138583721 is about 11772.1587230210. The cubic root of 138583721 is about 517.4925151585.

The spelling of 138583721 in words is "one hundred thirty-eight million, five hundred eighty-three thousand, seven hundred twenty-one".