400025641 has 2 divisors, whose sum is σ = 400025642. Its totient is φ = 400025640.

The previous prime is 400025629. The next prime is 400025663. The reversal of 400025641 is 146520004.

It is an a-pointer prime, because the next prime (400025663) can be obtained adding 400025641 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 236083225 + 163942416 = 15365^2 + 12804^2 .

It is a cyclic number.

It is not a de Polignac number, because 400025641 - 2¹⁷ = 399894569 is a prime.

400025641 is a modest number, since divided by 25641 gives 400 as remainder.

It is not a weakly prime, because it can be changed into another prime (400023641) 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, 200012820 + 200012821.

It is an arithmetic number, because the mean of its divisors is an integer number (200012821).

Almost surely, 2^400025641 is an apocalyptic number.

It is an amenable number.

400025641 is a deficient number, since it is larger than the sum of its proper divisors (1).

400025641 is an equidigital number, since it uses as much as digits as its factorization.

400025641 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 400025641 is about 20000.6410147275. The cubic root of 400025641 is about 736.8220431003.

Adding to 400025641 its reverse (146520004), we get a palindrome (546545645).

The spelling of 400025641 in words is "four hundred million, twenty-five thousand, six hundred forty-one".