138220812 has 72 divisors (see below), whose sum is σ = 375272352. Its totient is φ = 42739200.

The previous prime is 138220787. The next prime is 138220837. The reversal of 138220812 is 218022831.

It is an interprime number because it is at equal distance from previous prime (138220787) and next prime (138220837).

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 41862 + ... + 45042.

It is an arithmetic number, because the mean of its divisors is an integer number (5212116).

Almost surely, 2^138220812 is an apocalyptic number.

138220812 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138220812, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (187636176).

138220812 is an abundant number, since it is smaller than the sum of its proper divisors (237051540).

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

138220812 is a wasteful number, since it uses less digits than its factorization.

138220812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3279 (or 3274 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 138220812 is about 11756.7347507716. The cubic root of 138220812 is about 517.0404012988.

The spelling of 138220812 in words is "one hundred thirty-eight million, two hundred twenty thousand, eight hundred twelve".