400866121 has 2 divisors, whose sum is σ = 400866122. Its totient is φ = 400866120.

The previous prime is 400866113. The next prime is 400866163. The reversal of 400866121 is 121668004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 394419600 + 6446521 = 19860^2 + 2539^2 .

It is a cyclic number.

It is not a de Polignac number, because 400866121 - 2³ = 400866113 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 400866121.

It is not a weakly prime, because it can be changed into another prime (400861121) 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, 200433060 + 200433061.

It is an arithmetic number, because the mean of its divisors is an integer number (200433061).

Almost surely, 2^400866121 is an apocalyptic number.

400866121 is the 11560-th hex number.

It is an amenable number.

400866121 is a deficient number, since it is larger than the sum of its proper divisors (1).

400866121 is an equidigital number, since it uses as much as digits as its factorization.

400866121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 400866121 is about 20021.6413163357. The cubic root of 400866121 is about 737.3377191921.

The spelling of 400866121 in words is "four hundred million, eight hundred sixty-six thousand, one hundred twenty-one".