138865820 has 24 divisors (see below), whose sum is σ = 292705728. Its totient is φ = 55339200.

The previous prime is 138865819. The next prime is 138865823. The reversal of 138865820 is 28568831.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138865823) 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, 7391 + ... + 18230.

It is an arithmetic number, because the mean of its divisors is an integer number (12196072).

Almost surely, 2^138865820 is an apocalyptic number.

138865820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138865820 is an abundant number, since it is smaller than the sum of its proper divisors (153839908).

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

138865820 is a wasteful number, since it uses less digits than its factorization.

138865820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25901 (or 25899 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 41.

The square root of 138865820 is about 11784.1342490656. The cubic root of 138865820 is about 517.8434105775.

The spelling of 138865820 in words is "one hundred thirty-eight million, eight hundred sixty-five thousand, eight hundred twenty".