1643403401 has 2 divisors, whose sum is σ = 1643403402. Its totient is φ = 1643403400.

The previous prime is 1643403373. The next prime is 1643403427. The reversal of 1643403401 is 1043043461.

It is an a-pointer prime, because the next prime (1643403427) can be obtained adding 1643403401 to its sum of digits (26).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1030345801 + 613057600 = 32099^2 + 24760^2 .

It is a cyclic number.

It is not a de Polignac number, because 1643403401 - 2¹⁴ = 1643387017 is a prime.

It is not a weakly prime, because it can be changed into another prime (1643403301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821701700 + 821701701.

It is an arithmetic number, because the mean of its divisors is an integer number (821701701).

Almost surely, 2^1643403401 is an apocalyptic number.

It is an amenable number.

1643403401 is a deficient number, since it is larger than the sum of its proper divisors (1).

1643403401 is an equidigital number, since it uses as much as digits as its factorization.

1643403401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 1643403401 is about 40538.9121832345. The cubic root of 1643403401 is about 1180.0889047733.

Adding to 1643403401 its reverse (1043043461), we get a palindrome (2686446862).

The spelling of 1643403401 in words is "one billion, six hundred forty-three million, four hundred three thousand, four hundred one".