20728370509 has 16 divisors (see below), whose sum is σ = 25846718976. Its totient is φ = 16149754800.

The previous prime is 20728370479. The next prime is 20728370519. The reversal of 20728370509 is 90507382702.

It is a cyclic number.

It is not a de Polignac number, because 20728370509 - 2⁹ = 20728369997 is a prime.

It is a super-3 number, since 3×20728370509³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728370519) 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 15 ways as a sum of consecutive naturals, for example, 751134 + ... + 778240.

It is an arithmetic number, because the mean of its divisors is an integer number (1615419936).

Almost surely, 2^20728370509 is an apocalyptic number.

It is an amenable number.

20728370509 is a deficient number, since it is larger than the sum of its proper divisors (5118348467).

20728370509 is a wasteful number, since it uses less digits than its factorization.

20728370509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37056.

The product of its (nonzero) digits is 211680, while the sum is 43.

The spelling of 20728370509 in words is "twenty billion, seven hundred twenty-eight million, three hundred seventy thousand, five hundred nine".