138249647 has 4 divisors (see below), whose sum is σ = 139130376. Its totient is φ = 137368920.

The previous prime is 138249623. The next prime is 138249659. The reversal of 138249647 is 746942831.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 138249647 - 2¹⁸ = 137987503 is a prime.

It is a super-2 number, since 2×138249647² = 38225929791249218, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 138249598 and 138249607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138248647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 440129 + ... + 440442.

It is an arithmetic number, because the mean of its divisors is an integer number (34782594).

Almost surely, 2^138249647 is an apocalyptic number.

138249647 is a deficient number, since it is larger than the sum of its proper divisors (880729).

138249647 is an equidigital number, since it uses as much as digits as its factorization.

138249647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 880728.

The product of its digits is 290304, while the sum is 44.

The square root of 138249647 is about 11757.9610052083. The cubic root of 138249647 is about 517.0763530081.

The spelling of 138249647 in words is "one hundred thirty-eight million, two hundred forty-nine thousand, six hundred forty-seven".