400028231 has 4 divisors (see below), whose sum is σ = 400087752. Its totient is φ = 399968712.

The previous prime is 400028221. The next prime is 400028287. The reversal of 400028231 is 132820004.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-400028231 is a prime.

It is a super-2 number, since 2×400028231² = 320045171193978722, 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 (400028221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18176 + ... + 33621.

It is an arithmetic number, because the mean of its divisors is an integer number (100021938).

Almost surely, 2^400028231 is an apocalyptic number.

400028231 is a deficient number, since it is larger than the sum of its proper divisors (59521).

400028231 is an equidigital number, since it uses as much as digits as its factorization.

400028231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59520.

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 400028231 is about 20000.7057625475. The cubic root of 400028231 is about 736.8236333025.

Adding to 400028231 its reverse (132820004), we get a palindrome (532848235).

The spelling of 400028231 in words is "four hundred million, twenty-eight thousand, two hundred thirty-one".