181390900 has 54 divisors (see below), whose sum is σ = 399829010. Its totient is φ = 71427840.

The previous prime is 181390897. The next prime is 181390921. The reversal of 181390900 is 9093181.

It can be written as a sum of positive squares in 9 ways, for example, as 58890276 + 122500624 = 7674^2 + 11068^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 791986 + ... + 792214.

Almost surely, 2^181390900 is an apocalyptic number.

181390900 is a gapful number since it is divisible by the number (10) 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 181390900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (199914505).

181390900 is an abundant number, since it is smaller than the sum of its proper divisors (218438110).

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

181390900 is a wasteful number, since it uses less digits than its factorization.

181390900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421 (or 325 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 31.

The square root of 181390900 is about 13468.1438958752. The cubic root of 181390900 is about 566.0722062816.

The spelling of 181390900 in words is "one hundred eighty-one million, three hundred ninety thousand, nine hundred".