3898635661 has 2 divisors, whose sum is σ = 3898635662. Its totient is φ = 3898635660.

The previous prime is 3898635659. The next prime is 3898635703. The reversal of 3898635661 is 1665368983.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2947838436 + 950797225 = 54294^2 + 30835^2 .

It is a cyclic number.

It is not a de Polignac number, because 3898635661 - 2¹ = 3898635659 is a prime.

Together with 3898635659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3898635761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1949317830 + 1949317831.

It is an arithmetic number, because the mean of its divisors is an integer number (1949317831).

Almost surely, 2^3898635661 is an apocalyptic number.

It is an amenable number.

3898635661 is a deficient number, since it is larger than the sum of its proper divisors (1).

3898635661 is an equidigital number, since it uses as much as digits as its factorization.

3898635661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5598720, while the sum is 55.

The square root of 3898635661 is about 62439.0555742157. The cubic root of 3898635661 is about 1573.8773437108.

It can be divided in two parts, 38986 and 35661, that added together give a palindrome (74647).

The spelling of 3898635661 in words is "three billion, eight hundred ninety-eight million, six hundred thirty-five thousand, six hundred sixty-one".