138810 has 32 divisors (see below), whose sum is σ = 381312. Its totient is φ = 31680.

The previous prime is 138799. The next prime is 138821. The reversal of 138810 is 18831.

Added to its reverse (18831) it gives a triangular number (157641 = T₅₆₁).

138810 = 32² + 33² + ... + 76².

It is a happy number.

138810 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (138799) and next prime (138821).

It is a super-2 number, since 2×138810² = 38536432200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a nialpdrome in base 11.

It is an unprimeable number.

138810 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 121 + ... + 540.

It is an arithmetic number, because the mean of its divisors is an integer number (11916).

2¹³⁸⁸¹⁰ is an apocalyptic number.

138810 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

138810 is an abundant number, since it is smaller than the sum of its proper divisors (242502).

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

138810 is a wasteful number, since it uses less digits than its factorization.

138810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 678.

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 138810 is about 372.5721406654. The cubic root of 138810 is about 51.7774015308. Note that the first 3 decimals are identical.

Adding to 138810 its sum of digits (21), we get a palindrome (138831).

Adding to 138810 its reverse (18831), we get a triangular number (157641 = T₅₆₁).

The spelling of 138810 in words is "one hundred thirty-eight thousand, eight hundred ten".