400989 has 8 divisors (see below), whose sum is σ = 542272. Its totient is φ = 263520.

The previous prime is 400963. The next prime is 400997. The reversal of 400989 is 989004.

400989 = T₂₉₄ + T₂₉₅ + ... + T₃₀₂.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 400989 - 2¹¹ = 398941 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400949) 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 7 ways as a sum of consecutive naturals, for example, 697 + ... + 1134.

It is an arithmetic number, because the mean of its divisors is an integer number (67784).

2⁴⁰⁰⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

400989 is a deficient number, since it is larger than the sum of its proper divisors (141283).

400989 is a wasteful number, since it uses less digits than its factorization.

400989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1907.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 400989 is about 633.2369224864. The cubic root of 400989 is about 73.7413051130.

The spelling of 400989 in words is "four hundred thousand, nine hundred eighty-nine".