1638426473 has 2 divisors, whose sum is σ = 1638426474. Its totient is φ = 1638426472.

The previous prime is 1638426467. The next prime is 1638426497. The reversal of 1638426473 is 3746248361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1129833769 + 508592704 = 33613^2 + 22552^2 .

It is a cyclic number.

It is not a de Polignac number, because 1638426473 - 2⁴ = 1638426457 is a prime.

It is not a weakly prime, because it can be changed into another prime (1638426403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819213236 + 819213237.

It is an arithmetic number, because the mean of its divisors is an integer number (819213237).

Almost surely, 2^1638426473 is an apocalyptic number.

It is an amenable number.

1638426473 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638426473 is an equidigital number, since it uses as much as digits as its factorization.

1638426473 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 580608, while the sum is 44.

The square root of 1638426473 is about 40477.4810604613. The cubic root of 1638426473 is about 1178.8964289686.

The spelling of 1638426473 in words is "one billion, six hundred thirty-eight million, four hundred twenty-six thousand, four hundred seventy-three".