181390 has 32 divisors (see below), whose sum is σ = 381024. Its totient is φ = 61440.

The previous prime is 181387. The next prime is 181397. The reversal of 181390 is 93181.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181397) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1822 + ... + 1918.

It is an arithmetic number, because the mean of its divisors is an integer number (11907).

2¹⁸¹³⁹⁰ is an apocalyptic number.

181390 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

181390 is an abundant number, since it is smaller than the sum of its proper divisors (199634).

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

181390 is a wasteful number, since it uses less digits than its factorization.

181390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132.

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 181390 is about 425.8990490715. The cubic root of 181390 is about 56.6071270061.

Subtracting from 181390 its reverse (93181), we obtain a square (88209 = 297²).

The spelling of 181390 in words is "one hundred eighty-one thousand, three hundred ninety".