138261816 has 320 divisors, whose sum is σ = 514356480. Its totient is φ = 33592320.

The previous prime is 138261797. The next prime is 138261847. The reversal of 138261816 is 618162831.

138261816 is a `hidden beast` number, since 1 + 38 + 2 + 618 + 1 + 6 = 666.

138261816 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

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

Its product of digits (13824) is a multiple of the sum of its prime factors (216).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 848151 + ... + 848313.

It is an arithmetic number, because the mean of its divisors is an integer number (1607364).

Almost surely, 2^138261816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138261816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (257178240).

138261816 is an abundant number, since it is smaller than the sum of its proper divisors (376094664).

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

138261816 is a wasteful number, since it uses less digits than its factorization.

138261816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216 (or 203 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 138261816 is about 11758.4784729998. The cubic root of 138261816 is about 517.0915239149.

138261816 divided by its sum of digits (36) gives a triangular number (3840606 = T₂₇₇₁).

The spelling of 138261816 in words is "one hundred thirty-eight million, two hundred sixty-one thousand, eight hundred sixteen".