1638503641 has 2 divisors, whose sum is σ = 1638503642. Its totient is φ = 1638503640.

The previous prime is 1638503621. The next prime is 1638503689. The reversal of 1638503641 is 1463058361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1076102416 + 562401225 = 32804^2 + 23715^2 .

It is a cyclic number.

It is not a de Polignac number, because 1638503641 - 2¹³ = 1638495449 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1638503641.

It is not a weakly prime, because it can be changed into another prime (1638503611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819251820 + 819251821.

It is an arithmetic number, because the mean of its divisors is an integer number (819251821).

Almost surely, 2^1638503641 is an apocalyptic number.

It is an amenable number.

1638503641 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638503641 is an equidigital number, since it uses as much as digits as its factorization.

1638503641 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 1638503641 is about 40478.4342706088. The cubic root of 1638503641 is about 1178.9149368994.

The spelling of 1638503641 in words is "one billion, six hundred thirty-eight million, five hundred three thousand, six hundred forty-one".