398812181 has 4 divisors (see below), whose sum is σ = 399476364. Its totient is φ = 398148000.

The previous prime is 398812177. The next prime is 398812187. The reversal of 398812181 is 181218893.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 181218893 = 41 ⋅4419973.

It can be written as a sum of positive squares in 2 ways, for example, as 172791025 + 226021156 = 13145^2 + 15034^2 .

It is a cyclic number.

It is not a de Polignac number, because 398812181 - 2² = 398812177 is a prime.

It is a super-2 number, since 2×398812181² = 318102311427953522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398812187) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 331190 + ... + 332391.

It is an arithmetic number, because the mean of its divisors is an integer number (99869091).

Almost surely, 2^398812181 is an apocalyptic number.

It is an amenable number.

398812181 is a deficient number, since it is larger than the sum of its proper divisors (664183).

398812181 is an equidigital number, since it uses as much as digits as its factorization.

398812181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664182.

The product of its digits is 27648, while the sum is 41.

The square root of 398812181 is about 19970.2824466756. The cubic root of 398812181 is about 736.0762495091.

The spelling of 398812181 in words is "three hundred ninety-eight million, eight hundred twelve thousand, one hundred eighty-one".