1638420601 has 2 divisors, whose sum is σ = 1638420602. Its totient is φ = 1638420600.

The previous prime is 1638420599. The next prime is 1638420607. The reversal of 1638420601 is 1060248361.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1576010601 + 62410000 = 39699^2 + 7900^2 .

It is a cyclic number.

It is not a de Polignac number, because 1638420601 - 2¹ = 1638420599 is a prime.

Together with 1638420599, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1638420607) 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, 819210300 + 819210301.

It is an arithmetic number, because the mean of its divisors is an integer number (819210301).

Almost surely, 2^1638420601 is an apocalyptic number.

It is an amenable number.

1638420601 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638420601 is an equidigital number, since it uses as much as digits as its factorization.

1638420601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 1638420601 is about 40477.4085262384. The cubic root of 1638420601 is about 1178.8950206076.

Adding to 1638420601 its reverse (1060248361), we get a palindrome (2698668962).

The spelling of 1638420601 in words is "one billion, six hundred thirty-eight million, four hundred twenty thousand, six hundred one".