400388689 has 8 divisors (see below), whose sum is σ = 408180968. Its totient is φ = 392636160.

The previous prime is 400388671. The next prime is 400388699. The reversal of 400388689 is 986883004.

It can be written as a sum of positive squares in 4 ways, for example, as 2585664 + 397803025 = 1608^2 + 19945^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 400388689 - 2⁷ = 400388561 is a prime.

It is a super-2 number, since 2×400388689² = 320622204558277442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (400388699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10819 + ... + 30295.

It is an arithmetic number, because the mean of its divisors is an integer number (51022621).

Almost surely, 2^400388689 is an apocalyptic number.

It is an amenable number.

400388689 is a deficient number, since it is larger than the sum of its proper divisors (7792279).

400388689 is a wasteful number, since it uses less digits than its factorization.

400388689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19875.

The product of its (nonzero) digits is 331776, while the sum is 46.

The square root of 400388689 is about 20009.7148655347. The cubic root of 400388689 is about 737.0448795535.

The spelling of 400388689 in words is "four hundred million, three hundred eighty-eight thousand, six hundred eighty-nine".