138624816 has 80 divisors (see below), whose sum is σ = 394617600. Its totient is φ = 41583360.

The previous prime is 138624803. The next prime is 138624821. The reversal of 138624816 is 618426831.

It is a super-2 number, since 2×138624816² = 38433679222067712, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53110 + ... + 55658.

It is an arithmetic number, because the mean of its divisors is an integer number (4932720).

Almost surely, 2^138624816 is an apocalyptic number.

138624816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

138624816 is the 6798-th octagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138624816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (197308800).

138624816 is an abundant number, since it is smaller than the sum of its proper divisors (255992784).

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

138624816 is a wasteful number, since it uses less digits than its factorization.

138624816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2674 (or 2668 counting only the distinct ones).

The product of its digits is 55296, while the sum is 39.

The square root of 138624816 is about 11773.9040254284. The cubic root of 138624816 is about 517.5436617459.

The spelling of 138624816 in words is "one hundred thirty-eight million, six hundred twenty-four thousand, eight hundred sixteen".