402841981 has 2 divisors, whose sum is σ = 402841982. Its totient is φ = 402841980.

The previous prime is 402841963. The next prime is 402841997. The reversal of 402841981 is 189148204.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 324360100 + 78481881 = 18010^2 + 8859^2 .

It is a cyclic number.

It is not a de Polignac number, because 402841981 - 2¹³ = 402833789 is a prime.

It is a super-2 number, since 2×402841981² = 324563323312008722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 402841981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (402848981) 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, 201420990 + 201420991.

It is an arithmetic number, because the mean of its divisors is an integer number (201420991).

Almost surely, 2^402841981 is an apocalyptic number.

It is an amenable number.

402841981 is a deficient number, since it is larger than the sum of its proper divisors (1).

402841981 is an equidigital number, since it uses as much as digits as its factorization.

402841981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18432, while the sum is 37.

The square root of 402841981 is about 20070.9237704696. The cubic root of 402841981 is about 738.5471745242.

The spelling of 402841981 in words is "four hundred two million, eight hundred forty-one thousand, nine hundred eighty-one".