15550021649 has 2 divisors, whose sum is σ = 15550021650. Its totient is φ = 15550021648.

The previous prime is 15550021621. The next prime is 15550021681. The reversal of 15550021649 is 94612005551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14392321024 + 1157700625 = 119968^2 + 34025^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15550021649 is a prime.

It is not a weakly prime, because it can be changed into another prime (15550024649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7775010824 + 7775010825.

It is an arithmetic number, because the mean of its divisors is an integer number (7775010825).

Almost surely, 2^15550021649 is an apocalyptic number.

It is an amenable number.

15550021649 is a deficient number, since it is larger than the sum of its proper divisors (1).

15550021649 is an equidigital number, since it uses as much as digits as its factorization.

15550021649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54000, while the sum is 38.

The spelling of 15550021649 in words is "fifteen billion, five hundred fifty million, twenty-one thousand, six hundred forty-nine".