138849857 has 4 divisors (see below), whose sum is σ = 139091076. Its totient is φ = 138608640.

The previous prime is 138849839. The next prime is 138849889. The reversal of 138849857 is 758948831.

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

It can be written as a sum of positive squares in 2 ways, for example, as 79852096 + 58997761 = 8936^2 + 7681^2 .

It is a cyclic number.

It is not a de Polignac number, because 138849857 - 2⁶ = 138849793 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 138849799 and 138849808.

It is not an unprimeable number, because it can be changed into a prime (138849817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 119744 + ... + 120897.

It is an arithmetic number, because the mean of its divisors is an integer number (34772769).

Almost surely, 2^138849857 is an apocalyptic number.

It is an amenable number.

138849857 is a deficient number, since it is larger than the sum of its proper divisors (241219).

138849857 is an equidigital number, since it uses as much as digits as its factorization.

138849857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241218.

The product of its digits is 1935360, while the sum is 53.

The square root of 138849857 is about 11783.4569206154. The cubic root of 138849857 is about 517.8235673189.

The spelling of 138849857 in words is "one hundred thirty-eight million, eight hundred forty-nine thousand, eight hundred fifty-seven".