400127561 has 2 divisors, whose sum is σ = 400127562. Its totient is φ = 400127560.

The previous prime is 400127549. The next prime is 400127603. The reversal of 400127561 is 165721004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 268337161 + 131790400 = 16381^2 + 11480^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-400127561 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 400127561.

It is not a weakly prime, because it can be changed into another prime (400127461) 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 as a sum of consecutive naturals, namely, 200063780 + 200063781.

It is an arithmetic number, because the mean of its divisors is an integer number (200063781).

Almost surely, 2^400127561 is an apocalyptic number.

It is an amenable number.

400127561 is a deficient number, since it is larger than the sum of its proper divisors (1).

400127561 is an equidigital number, since it uses as much as digits as its factorization.

400127561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 400127561 is about 20003.1887707935. The cubic root of 400127561 is about 736.8846145274.

Adding to 400127561 its reverse (165721004), we get a palindrome (565848565).

The spelling of 400127561 in words is "four hundred million, one hundred twenty-seven thousand, five hundred sixty-one".