138878166 has 16 divisors (see below), whose sum is σ = 317435904. Its totient is φ = 39679464.

The previous prime is 138878161. The next prime is 138878167. The reversal of 138878166 is 661878831.

138878166 is nontrivially palindromic in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138878161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1653270 + ... + 1653353.

It is an arithmetic number, because the mean of its divisors is an integer number (19839744).

Almost surely, 2^138878166 is an apocalyptic number.

138878166 is an abundant number, since it is smaller than the sum of its proper divisors (178557738).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138878166 is a wasteful number, since it uses less digits than its factorization.

138878166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3306635.

The product of its digits is 387072, while the sum is 48.

The square root of 138878166 is about 11784.6580773479. The cubic root of 138878166 is about 517.8587565791.

The spelling of 138878166 in words is "one hundred thirty-eight million, eight hundred seventy-eight thousand, one hundred sixty-six".