138278501 has 2 divisors, whose sum is σ = 138278502. Its totient is φ = 138278500.

The previous prime is 138278479. The next prime is 138278513. The reversal of 138278501 is 105872831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 98525476 + 39753025 = 9926^2 + 6305^2 .

It is an emirp because it is prime and its reverse (105872831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138278501 - 2¹⁸ = 138016357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138278531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69139250 + 69139251.

It is an arithmetic number, because the mean of its divisors is an integer number (69139251).

Almost surely, 2^138278501 is an apocalyptic number.

It is an amenable number.

138278501 is a deficient number, since it is larger than the sum of its proper divisors (1).

138278501 is an equidigital number, since it uses as much as digits as its factorization.

138278501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13440, while the sum is 35.

The square root of 138278501 is about 11759.1879396496. The cubic root of 138278501 is about 517.1123234032.

The spelling of 138278501 in words is "one hundred thirty-eight million, two hundred seventy-eight thousand, five hundred one".