400128730 has 16 divisors (see below), whose sum is σ = 739698120. Its totient is φ = 155725632.

The previous prime is 400128727. The next prime is 400128731. The reversal of 400128730 is 37821004.

It can be written as a sum of positive squares in 4 ways, for example, as 373223761 + 26904969 = 19319^2 + 5187^2 .

It is a junction number, because it is equal to n+sod(n) for n = 400128695 and 400128704.

It is not an unprimeable number, because it can be changed into a prime (400128731) 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 7 ways as a sum of consecutive naturals, for example, 540345 + ... + 541084.

Almost surely, 2^400128730 is an apocalyptic number.

400128730 is a deficient number, since it is larger than the sum of its proper divisors (339569390).

400128730 is a wasteful number, since it uses less digits than its factorization.

400128730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1081473.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 400128730 is about 20003.2179911133. The cubic root of 400128730 is about 736.8853321463.

Adding to 400128730 its reverse (37821004), we get a palindrome (437949734).

The spelling of 400128730 in words is "four hundred million, one hundred twenty-eight thousand, seven hundred thirty".