400281989 has 4 divisors (see below), whose sum is σ = 400322124. Its totient is φ = 400241856.

The previous prime is 400281979. The next prime is 400281991. The reversal of 400281989 is 989182004.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 91049764 + 309232225 = 9542^2 + 17585^2 .

It is a cyclic number.

It is not a de Polignac number, because 400281989 - 2⁸ = 400281733 is a prime.

It is a super-2 number, since 2×400281989² = 320451341435592242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400281929) 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 3 ways as a sum of consecutive naturals, for example, 7709 + ... + 29325.

It is an arithmetic number, because the mean of its divisors is an integer number (100080531).

Almost surely, 2^400281989 is an apocalyptic number.

It is an amenable number.

400281989 is a deficient number, since it is larger than the sum of its proper divisors (40135).

400281989 is a wasteful number, since it uses less digits than its factorization.

400281989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40134.

The product of its (nonzero) digits is 41472, while the sum is 41.

The square root of 400281989 is about 20007.0484829722. The cubic root of 400281989 is about 736.9794017834.

The spelling of 400281989 in words is "four hundred million, two hundred eighty-one thousand, nine hundred eighty-nine".