398787 has 4 divisors (see below), whose sum is σ = 531720. Its totient is φ = 265856.

The previous prime is 398771. The next prime is 398813. The reversal of 398787 is 787893.

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 398787 - 2⁴ = 398771 is a prime.

It is a D-number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 398787.

It is not an unprimeable number, because it can be changed into a prime (398087) 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, 66462 + ... + 66467.

It is an arithmetic number, because the mean of its divisors is an integer number (132930).

2³⁹⁸⁷⁸⁷ is an apocalyptic number.

398787 is a deficient number, since it is larger than the sum of its proper divisors (132933).

398787 is a wasteful number, since it uses less digits than its factorization.

398787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132932.

The product of its digits is 84672, while the sum is 42.

The square root of 398787 is about 631.4958432167. The cubic root of 398787 is about 73.6060757232.

It can be divided in two parts, 3 and 98787, that added together give a triangular number (98790 = T₄₄₄).

The spelling of 398787 in words is "three hundred ninety-eight thousand, seven hundred eighty-seven".