138640730 has 8 divisors (see below), whose sum is σ = 249553332. Its totient is φ = 55456288.

The previous prime is 138640709. The next prime is 138640753. The reversal of 138640730 is 37046831.

138640730 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 112763161 + 25877569 = 10619^2 + 5087^2 .

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, 6932027 + ... + 6932046.

Almost surely, 2^138640730 is an apocalyptic number.

138640730 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

138640730 is a deficient number, since it is larger than the sum of its proper divisors (110912602).

138640730 is a wasteful number, since it uses less digits than its factorization.

138640730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13864080.

The product of its (nonzero) digits is 12096, while the sum is 32.

The square root of 138640730 is about 11774.5798226518. The cubic root of 138640730 is about 517.5634654985.

The spelling of 138640730 in words is "one hundred thirty-eight million, six hundred forty thousand, seven hundred thirty".