400987 has 4 divisors (see below), whose sum is σ = 402696. Its totient is φ = 399280.

The previous prime is 400963. The next prime is 400997. The reversal of 400987 is 789004.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 400987 - 2⁷ = 400859 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (400927) 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 3 ways as a sum of consecutive naturals, for example, 433 + ... + 994.

It is an arithmetic number, because the mean of its divisors is an integer number (100674).

2⁴⁰⁰⁹⁸⁷ is an apocalyptic number.

400987 is a deficient number, since it is larger than the sum of its proper divisors (1709).

400987 is a wasteful number, since it uses less digits than its factorization.

400987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1708.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 400987 is about 633.2353432966. The cubic root of 400987 is about 73.7411825138.

It can be divided in two parts, 4009 and 87, that added together give a 12-th power (4096 = 2¹²).

The spelling of 400987 in words is "four hundred thousand, nine hundred eighty-seven".