9815544649 has 2 divisors, whose sum is σ = 9815544650. Its totient is φ = 9815544648.

The previous prime is 9815544637. The next prime is 9815544703. The reversal of 9815544649 is 9464455189.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9471182400 + 344362249 = 97320^2 + 18557^2 .

It is a cyclic number.

It is not a de Polignac number, because 9815544649 - 2¹³ = 9815536457 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 9815544649.

It is not a weakly prime, because it can be changed into another prime (9815541649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4907772324 + 4907772325.

It is an arithmetic number, because the mean of its divisors is an integer number (4907772325).

Almost surely, 2^9815544649 is an apocalyptic number.

It is an amenable number.

9815544649 is a deficient number, since it is larger than the sum of its proper divisors (1).

9815544649 is an equidigital number, since it uses as much as digits as its factorization.

9815544649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6220800, while the sum is 55.

The square root of 9815544649 is about 99073.4305906483. The cubic root of 9815544649 is about 2141.1058314311.

The spelling of 9815544649 in words is "nine billion, eight hundred fifteen million, five hundred forty-four thousand, six hundred forty-nine".