402808561 has 2 divisors, whose sum is σ = 402808562. Its totient is φ = 402808560.

The previous prime is 402808547. The next prime is 402808573. The reversal of 402808561 is 165808204.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 322884961 + 79923600 = 17969^2 + 8940^2 .

It is a cyclic number.

It is not a de Polignac number, because 402808561 - 2¹³ = 402800369 is a prime.

It is not a weakly prime, because it can be changed into another prime (402808541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201404280 + 201404281.

It is an arithmetic number, because the mean of its divisors is an integer number (201404281).

Almost surely, 2^402808561 is an apocalyptic number.

It is an amenable number.

402808561 is a deficient number, since it is larger than the sum of its proper divisors (1).

402808561 is an equidigital number, since it uses as much as digits as its factorization.

402808561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15360, while the sum is 34.

The square root of 402808561 is about 20070.0912055725. The cubic root of 402808561 is about 738.5267505281.

It can be divided in two parts, 40280 and 8561, that added together give a square (48841 = 221²).

The spelling of 402808561 in words is "four hundred two million, eight hundred eight thousand, five hundred sixty-one".