20998734149 has 18 divisors (see below), whose sum is σ = 22091381190. Its totient is φ = 19936339920.

The previous prime is 20998734103. The next prime is 20998734179. The reversal of 20998734149 is 94143789902.

It can be written as a sum of positive squares in only one way, i.e., 18102357025 + 2896377124 = 134545^2 + 53818^2 .

It is not a de Polignac number, because 20998734149 - 2³² = 16703766853 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20998734094 and 20998734103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20998734179) 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 17 ways as a sum of consecutive naturals, for example, 55405442 + ... + 55405820.

It is an arithmetic number, because the mean of its divisors is an integer number (1227298955).

Almost surely, 2^20998734149 is an apocalyptic number.

20998734149 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20998734149 is a deficient number, since it is larger than the sum of its proper divisors (1092647041).

20998734149 is an frugal number, since it uses more digits than its factorization.

20998734149 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 929 (or 479 counting only the distinct ones).

The product of its (nonzero) digits is 3919104, while the sum is 56.

The spelling of 20998734149 in words is "twenty billion, nine hundred ninety-eight million, seven hundred thirty-four thousand, one hundred forty-nine".