138620506 has 4 divisors (see below), whose sum is σ = 207930762. Its totient is φ = 69310252.

The previous prime is 138620497. The next prime is 138620507. The reversal of 138620506 is 605026831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 605026831 = 11059 ⋅54709.

It can be written as a sum of positive squares in only one way, i.e., 101909025 + 36711481 = 10095^2 + 6059^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (138620507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34655125 + ... + 34655128.

Almost surely, 2^138620506 is an apocalyptic number.

138620506 is a deficient number, since it is larger than the sum of its proper divisors (69310256).

138620506 is an equidigital number, since it uses as much as digits as its factorization.

138620506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69310255.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 138620506 is about 11773.7209921078. The cubic root of 138620506 is about 517.5382980206.

The spelling of 138620506 in words is "one hundred thirty-eight million, six hundred twenty thousand, five hundred six".