400816 has 40 divisors (see below), whose sum is σ = 874944. Its totient is φ = 176640.

The previous prime is 400759. The next prime is 400823. The reversal of 400816 is 618004.

400816 = T₅₅ + T₅₆ + ... + T₁₃₆.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 400793 and 400802.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8505 + ... + 8551.

2⁴⁰⁰⁸¹⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 400816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (437472).

400816 is an abundant number, since it is smaller than the sum of its proper divisors (474128).

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

400816 is a wasteful number, since it uses less digits than its factorization.

400816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109 (or 103 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 400816 is about 633.1003080081. The cubic root of 400816 is about 73.7306987698.

The spelling of 400816 in words is "four hundred thousand, eight hundred sixteen".