20998038649 has 27 divisors (see below), whose sum is σ = 24772107717. Its totient is φ = 17747050104.

The previous prime is 20998038643. The next prime is 20998038653. The reversal of 20998038649 is 94683089902.

The square root of 20998038649 is 144907.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 20998038649 - 2¹³ = 20998030457 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20998038593 and 20998038602.

It is not an unprimeable number, because it can be changed into a prime (20998038643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 128822242 + ... + 128822404.

It is an arithmetic number, because the mean of its divisors is an integer number (917485471).

Almost surely, 2^20998038649 is an apocalyptic number.

20998038649 is the 144907-th square number.

20998038649 is the 72454-th centered octagonal number.

It is an amenable number.

20998038649 is a deficient number, since it is larger than the sum of its proper divisors (3774069068).

20998038649 is an frugal number, since it uses more digits than its factorization.

20998038649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 594 (or 297 counting only the distinct ones).

The product of its (nonzero) digits is 6718464, while the sum is 58.

The spelling of 20998038649 in words is "twenty billion, nine hundred ninety-eight million, thirty-eight thousand, six hundred forty-nine".