400161 has 4 divisors (see below), whose sum is σ = 533552. Its totient is φ = 266772.

The previous prime is 400157. The next prime is 400187. The reversal of 400161 is 161004.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 400161 - 2² = 400157 is a prime.

It is a super-3 number, since 3×400161³ = 192231933328119843, which contains 333 as substring.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (400151) 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, 66691 + ... + 66696.

It is an arithmetic number, because the mean of its divisors is an integer number (133388).

2⁴⁰⁰¹⁶¹ is an apocalyptic number.

It is an amenable number.

400161 is a deficient number, since it is larger than the sum of its proper divisors (133391).

400161 is a wasteful number, since it uses less digits than its factorization.

400161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133390.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 400161 is about 632.5828009044. The cubic root of 400161 is about 73.6905141313.

Adding to 400161 its reverse (161004), we get a palindrome (561165).

It can be divided in two parts, 400 and 161, that added together give a triangular number (561 = T₃₃).

The spelling of 400161 in words is "four hundred thousand, one hundred sixty-one".