400869 has 30 divisors (see below), whose sum is σ = 703494. Its totient is φ = 226800.

The previous prime is 400859. The next prime is 400871. The reversal of 400869 is 968004.

It can be written as a sum of positive squares in only one way, i.e., 396900 + 3969 = 630^2 + 63^2 .

It is not a de Polignac number, because 400869 - 2⁴ = 400853 is a prime.

It is a super-2 number, since 2×400869² = 321391910322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

400869 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 3919 + ... + 4019.

2⁴⁰⁰⁸⁶⁹ is an apocalyptic number.

400869 is a gapful number since it is divisible by the number (49) formed by its first and last digit.

It is an amenable number.

400869 is a deficient number, since it is larger than the sum of its proper divisors (302625).

400869 is a wasteful number, since it uses less digits than its factorization.

400869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127 (or 111 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 400869 is about 633.1421641306. The cubic root of 400869 is about 73.7339484362.

The spelling of 400869 in words is "four hundred thousand, eight hundred sixty-nine".