20219986809 has 81 divisors (see below), whose sum is σ = 33412532517. Its totient is φ = 11773911600.

The previous prime is 20219986733. The next prime is 20219986811. The reversal of 20219986809 is 90868991202.

The square root of 20219986809 is 142197.

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

It is not a de Polignac number, because 20219986809 - 2¹¹ = 20219984761 is a prime.

It is a super-2 number, since 2×20219986809² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20219986859) 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 80 ways as a sum of consecutive naturals, for example, 145467462 + ... + 145467600.

Almost surely, 2^20219986809 is an apocalyptic number.

20219986809 is the 142197-th square number.

20219986809 is the 71099-th centered octagonal number.

It is an amenable number.

20219986809 is a deficient number, since it is larger than the sum of its proper divisors (13192545708).

20219986809 is a wasteful number, since it uses less digits than its factorization.

20219986809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 368 (or 184 counting only the distinct ones).

The product of its (nonzero) digits is 1119744, while the sum is 54.

The spelling of 20219986809 in words is "twenty billion, two hundred nineteen million, nine hundred eighty-six thousand, eight hundred nine".